Despite teleosts being the largest and most diverse group of vertebrates, fish models currently used to study photoperiodic effects on fish physiology have been limited to a few species, most of which are temperate seasonal breeders. The overall aim of this work was to expand our knowledge on circadian biology and environmental physiological effects in Nile tilapia (Oreochromis niloticus niloticus), a continuous breeding species of tropical-subtropical origin. The circadian light axis of Nile tilapia is described with regards to melatonin production. Circadian melatonin profiles of fish under 12L:12D photoperiods were observed to be low at day and high at night, suggesting melatonin to be an entraining signal as observed in all other vertebrates. When constant light (LL) was used, such day and night fluctuations where abolished. However when fish where exposed to constant darkness (DD) a strong robust endogenous melatonin rhythm was found, suggesting the presence of circadian oscillators in this ...
Pseudomonas aeruginosa (P. aeruginosa) produces a suite of virulence factors that are coordinated by Quorum Sensing (QS) contributing to its disease-causing ability in aquaculture. The present study is first of its kind to obtain information regarding the presence and distribution of five QS genes, three virulence genes viz: lasI, lasR, rhlI, rhlR, rhlAB, toxA, aprA and plcH and seven of the Extended-spectrum βlactamases (blaVEB, blaPER, blaTEM,, blaSHV, blaCTX-M1, blaCTX-M2 and blaCTX-M3) of Pseudomonas species isolated from fish meat by direct PCR. Bacterial identification was based mainly on conventional biochemical techniques using the Vitek 2, automated system. Phenotypic sensitivity of antibiotics was established by the agar disc diffusion technique through 16 various antimicrobial drugs. Quantification of their in vitro production of numerous virulence genes outside the cell that are QS dependent namely, pyocyanin, elastase, alkaline protease, biofilm and cytotoxicity of Vero cell was as
Sex chromosomes change more frequently in fish than in mammals or birds. However, certain chromosomes or genes are repeatedly used as sex determinants in different members of the teleostean lineage. East African cichlids are an enigmatic model system in evolutionary biology representing some of the most diverse extant vertebrate adaptive radiations. How sex is determined and if different sex-determining mechanisms contribute to speciation is unknown for almost all of the over 1,500 cichlid species of the Great Lakes. Here, we investigated the genetic basis of sex determination in a cichlid from Lake Tanganyika, Astatotilapia burtoni, a member of the most species-rich cichlid lineage, the haplochromines. We used RAD-sequencing of crosses for two populations of A. burtoni, a lab strain and fish caught at the south of Lake Tanganyika. Using association mapping and comparative genomics, we confirmed male heterogamety in A. burtoni and identified different sex chromosomes (LG5 and LG18) in the two
article{9cc27631-773b-4625-add5-aeb353c7d0cb, abstract = {,p,Parasite diversity and abundance (parasite load) vary greatly among host species. However, the influence of host traits on variation in parasitism remains poorly understood. Comparative studies of parasite load have largely examined measures of parasite species richness and are predominantly based on records obtained from published data. Consequently, little is known about the relationships between host traits and other aspects of parasite load, such as parasite abundance, prevalence and aggregation. Meanwhile, understanding of parasite species richness may be clouded by limitations associated with data collation from multiple independent sources. We conducted a field study of Lake Tanganyika cichlid fishes and their helminth parasites. Using a Bayesian phylogenetic comparative framework, we tested evolutionary associations between five key host traits (body size, gut length, diet breadth, habitat complexity and number of sympatric ...
Cichlids are a diverse group of fish from the family Cichlidae. There are an estimated 1300 to 3000 species of cichlids. They come in a variety of shapes and sizes, ranging from 2.5 cm to 1 meter in length and can live for 4-10 years. Cichlids originated in Africa but can be found in South America as well; most notably, they are found in Lake Malawi, Lake Tanganyika and Lake Victoria. In Lake Malawi alone, there are an estimated 1,000 different types of cichlid species (Evolutionary Biology). They prefer fresh to brackish water and usually live near the waters surface. Many cichlids are herbivores that feed on algae, but some are predatory and consume other small fish or insect larvaes.. Why study Cichlids? Cichlids are great model organisms to study because they represent rapid and convergent evolutionary radiation in vertebrates. Also, there is a large variety of cichlids which makes it easier for scientists to study multiple phenotypic traits.. Cichlid Reproduction. Cichlids demonstrate four ...
The hundreds of endemic species of cichlid fishes in the East African Great Lakes Tanganyika, Malawi, and Victoria are a prime model system in evolutionary biology. With five genomes currently being sequenced, eastern African cichlids also represent a forthcoming genomic model for evolutionary studies of genotype-to-phenotype processes in adaptive radiations. Here we report the functional annotation and comparative analyses of transcriptome data sets for two eastern African cichlid species, Astatotilapia burtoni and Ophthalmotilapia ventralis, representatives of the modern haplochromines and ectodines, respectively. Nearly 647,000 expressed sequence tags were assembled in more than 46,000 contigs for each species using the 454 sequencing technology, largely expanding the current sequence data set publicly available for these cichlids. Total predicted coverage of their proteome diversity is approximately 50% for both species. Comparative qualitative and quantitative analyses show very similar ...
Our research program uses fishes, and specifically the African cichlid fish Astatotilapia burtoni (see Model System page), as models to study how the brain processes information, how sensory systems contribute to behavior, and how natural plasticity in an animals internal hormonal or nutritional state can influence neural function and behavioral outcomes. Fishes are the largest and most diverse group of vertebrates, which provides us with ideal organisms to study basic neuron and sensory function, and how it relates to proximate and ultimate behavioral mechanisms in comparative and evolutionary contexts. ...
Synonyms for Convict cichlid in Free Thesaurus. Antonyms for Convict cichlid. 3 synonyms for convict fish: convictfish, Oxylebius pictus, painted greenling. What are synonyms for Convict cichlid?
B chromosomes have a functional effect on sex determination in a species of cichlid fishes from Lake Victoria [...] The researchers found sex-ratio distortions caused by B chromosomes in the breeding line of the cichlids, as well as several protein-coding genes in the B chromosomes. The resultant ratio was female biased, suggesting a role for B chromosomes in female sex determination. [...] In the present study, the researchers performed an extensive analysis of B chromosomes in cichlid fishes from Lake Victoria to investigate their effect on cichlid evolution. Karyotype analysis of Lake Victoria cichlids suggested that, in one species, Lithochromis rubripinnis, there are female-specific B chromosomes. Crossbreeding experiments suggested that an effector of female sex determination in this species was the B chromosome. Furthermore, analyses of large-scale sequences of B chromosomes in Lake Victoria cichlids revealed multiple protein-coding genes in B chromosomes. The sex determination gene was ...
African Cichlids - Mbuna, Haps and Peacock Cichlids from African rift lakes, Lake Malawi, Victoria and Tanganyika. Hardy fish for specialty aquariums.
Cheers, Neale.,. Tank Mates?? Oscar comp./sys., Neotrop. cichlids period 08/28/08 Hello there, I have emailed you guys before about some of my tanks and ideas about new tanks and have received great advice! Now i have a question about my tiger Oscar cichlid who is about 8 inches long and pretty docile. I am soon moving him to a larger tank hopefully 75 gallons but maybe 55. And i was wondering about some tank mates for him. ,Not in the 55... too small, I am very interested in more South American cichlids. I have a particular interest in maybe getting a jack Dempsey? But i do know Jacks are pretty aggressive and territorial thats why i am consulting you guys. Another cichlid i was considering was a green terror but im not sure if the adult size of one could or would grow up to being as big as my Oscar because i have read that they only grow to be 8 inches in length. Lastly i was considering a blue Acara or a jaguar cichlid but my problem with these two are i have no idea how big they get. Could ...
Jewel Cichlid Acting Strange 1/2/07 Hi- I have a 55 gallon tank with 1 Kenyi cichlid, 1 Bumblebee cichlid, 1 hybrid cichlid, 1 orange cichlid (?), 1 red tip shark, 1 Pleco and a jewel cichlid. The jewel cichlid (which is a pearl color with blue dots) has been acting strange lately. She does not swim around only stays at the top of the tank. Her fins are all down and she curves her tailfin. She eats a little but not like she use to. She does not swim around although she has always kept to herself but now she is not acting normal. I have isolated her in a tank but I am at a loss as to what to do for her. Any advice would be appreciated. Thanks! Leslie , Clamped fins are a sign of a disease. Treat with Rid-Ich and salt for now. Crank the temp up to 82 F. If not better in three days then do a 50% water change and treat with Nitrofuranace and salt.-Chuck, Bumps on FW Fish - 1/22/07 A quick note for todays post Bumps on FW Fish in which Chuck suggested treating the fish with Nitrofurazone. The ...
Fish guide for Angelfish, Pterophyllum scalare, Freshwater Angelfish facts with fish pictures, description and information, types of freshwater angelfish, Silver Angelfish care, aquarium habitat and fish diseases, Angelfish tank mates, compatibility and breeding
Fish guide for Sardine Cichlid, Cyprichromis leptosoma profile with fish pictures, description and information, Slender Cichlid care, diet, habitat and fish diseases, tank mates, Slender Cichlid breeding, compatibility and keeping the Xenotilapia sp. Blue Flash cichlid aquarium, Slender Cyp, Neonback, Lepto Cichlid
Detail záznamu - Phylogeny of the Neotropical cichlid fish tribe Cichlasomatini (Teleostei: Cichlidae) based on morphological and molecular data, with the description of a new genus - Detail záznamu - Knihovna Akademie věd České republiky
Fish guide for Sexfasciatus, Neolamprologus sexfasciatus profile with fish pictures, description and information, Gold Sexfasciatus Cichlid care, diet, habitat and fish diseases, Sexfasciatus cichlid breeding, tank mates, compatibility and keeping the Sexfasciatus aquarium, Six-bar Lamprologus, Six Bar Cichlid
Tilapia Oreochromis niloticus is an aquaculture resource that represents one of the most popular crops in the world. However, species cultivation presents health proble..
Fish guide for White-Tailed Brichardi, Neolamprologus gracilis profile with fish pictures, description and information, Gracilis Cichlid care, diet, habitat and fish diseases, Neolamprologus gracilis breeding, tank mates, compatibility and keeping the Graceful Lamprologus aquarium, Blue-tail Brichardi
Oreochromis niloticus DMO protein: DMO - DM-domain gene in ovary; isolated from the fish Tilapia, Oreochromis niloticus; amino acid sequence in first source; GenBank AF203490
The ram cichlid, Mikrogeophagus ramirezi, is a species of freshwater fish endemic to the Orinoco River basin, in the savannahs of Venezuela and Colombia in South America. The species has been examined in studies on fish behaviour and is a popular aquarium fish, traded under a variety of common names, including ram, blue ram, German blue ram, Asian ram, butterfly cichlid, Ramirezs dwarf cichlid, dwarf butterfly cichlid and Ramirezi. The species is a member of the family Cichlidae and subfamily Geophaginae. Wild ram cichlids are often more colorful than the tank-bred fish, which suffer from poor breeding and also being injected with hormones for more color, although this makes as many as one in four males infertile.[citation needed] Male specimens of the ram usually have the first few rays of the dorsal fin extended, but breeding has made some females also show this. When close to spawning, female rams have a pink or red blush on the abdomen. Females also have a blue sheen over the spot just ...
Utahs premier Freshwater African Cichlid breeder with several species of African cichlids for sale. Call 801-572-2009 to buy your Malawi Cichlids at Live Fish Direct
Utahs premier Freshwater African Cichlid breeder with several species of African cichlids for sale. Call 801-572-2009 to buy your Malawi Cichlids at Live Fish Direct
Many shell-dwelling species are adaptations of these cave spawners and include Neolamprologus ocellatus. Their caves are made up of the empty, calcified shells of Neothauma snails which are preserved by the hard alkaline water. Shell dwellers can be kept in small tanks and make fascinating residents.. Mouthbrooders. These are also very popular with hobbyists, with the rock dwelling, algae grazing Tropheus, the large sedate, predatory Frontosa and the slender, open water Sardine cichlids making up the bulk of all such fish sold. The three are very different in their requirements, despite inhabiting the same lake, so should not be kept together in the same tank.. Tropheus look and behave like Pseudotropheus from Lake Malawi. Their diet is poor, consisting of short algae strands growing from rocks and the odd invertebrate found within the algae. This growth is commonly referred to as aufwuch. Tropheus are aggressive and territorial in the aquarium, as in nature they fight to protect their algae and ...
Population boundaries are largely determined by local environment, the strength of barriers to migration, and the organisms inherent dispersal abilities. The interaction among these and genetic factors determines the potential for evolutionary divergence, and is at the heart of our understanding of ecological adaptation and ongoing speciation processes. When individuals can easily cross barriers between suitable habitat patches, gene flow acts to homogenize most neutral genetic diversity and may swamp the effects of any local phenotypic selection whereas low levels of migration may facilitate ecological divergence, even when selection is modest. Evolutionary divergence through fine-scale geographic isolation is believed to be one of the main mechanisms promoting speciation in the cichlid radiations of the African Great Lakes [1-3]. Many lake species are extreme local endemics, with distributions limited to small patches of ecologically distinct habitat. Many narrowly endemic cichlid species are ...
Background Cichlid fishes have radiated into hundreds of species in the Great Lakes of Africa. Brightly colored males display on leks and vie to be chosen by females as mates. Strong discrimination by females causes differential male mating success, rapid evolution of male color patterns and, possibly, speciation. In addition to differences in color pattern, Lake Malawi cichlids also show some of the largest known shifts in visual sensitivity among closely related species. These shifts result from modulated expression of seven cone opsin genes. However, the mechanisms for this modulated expression are unknown. Results In this work, we ask whether these differences might result from changes in developmental patterning of cone opsin genes. To test this, we compared the developmental pattern of cone opsin gene expression of the Nile tilapia, Oreochromis niloticus, with that of several cichlid species from Lake Malawi. In tilapia, quantitative polymerase chain reaction showed that opsin gene ...
The proportion of assembled haplochromine cichlid sequences with and without BLAST matches compared to three databases (Takifugu rubripes, Danio rerio, and Onco
The firemouth cichlid (Thorichthys meeki) is a species of cichlid fish native to Central America. They occur in rivers of the Yucatán Peninsula, Mexico, south through Belize and into northern Guatemala. Their natural habitat is typically shallow, slow-moving, often turbid, water with a pH of 6.5 - 8.0. It has also been reported to live in underground cave systems. As fish with a tropical distribution, firemouth cichlids live in warm water with a temperature range of 23-30 °C (75-86 °F). The common name, firemouth, is derived from the bright orange-red colouration on the underside of the jaw. Males in particular flare out their gills, exposing their red throats, in a threat display designed to ward off male rivals from their territory. Like most cichlids, brood care is highly developed; this species is an egg-layer. Firemouth cichlids form monogamous pairs and spawn on flattened surfaces of rocks, leaves or submerged wood. Breeding males are primarily responsible for territorial defense, while ...
Neotropical Cichlid Phylogeny - Tropical fish forum at the Age of Aquariums - dedicated to promoting responsible fish-keeping internationally.
Convict Cichlids is a kind of fish also known as Zebra Cichlids to aquarium enthusiasts. They are relatively easy to breed because they require minimal human supervision or intervention.
... Wardley Premium Cichlid Floating Pellets (Medium) provide a balanced diet for growth, superior coloration and survival of both herbivorous and carnivorous cichlids. Provides a balanced diet for growth Promtes superior colora...
In this study, we wanted to take the first step in understanding vision in cichlids and to know whether they have true color vision. Further studies are needed to dissect the cichlid visual system as well as its adaptations and limitations but, given our visual modeling and behavioral results, we can infer the physiological characteristics of the cichlid retina. Initially, based on previous fish-vision studies applying the RNL model, we assumed a Weber fraction of 0.05 (Champ et al., 2016; Cheney et al., 2009; Dalton et al., 2016; Wilkins et al., 2016) for the LWS channel. However, in order to better predict cichlid performance, we adjusted this to a higher Weber fraction of 0.1. We did this because, even though we are not evaluating color discrimination thresholds, increasing the Weber fraction, and hence lowering chromatic distance, would partially explain the mistakes fish made (Figs 2 and 3). In general, a Weber fraction of 0.05 is accepted for most animals (Vorobyev and Osorio, 1998) but it ...
Although it is widely assumed that the evolution of jaw kinesis in the ray-finned fishes was an innovation to enhance suction feeding performance, the lack of phylogenetic replication of this event across fishes has hindered direct tests of this hypothesis. Our results reveal that within the East African cichlid radiations, multiple transitions between biting and suction feeding have occurred, and that these functional transitions are accompanied by evolutionary reduction of jaw kinesis over short evolutionary timescales of 4 Myr or less (figure 3). These rapid and repeated shifts are consistent with the hypothesis that high jaw kinesis is selectively maintained in suction feeding fishes and provides evidence supporting upper jaw protrusion as a major evolutionary innovation for ray-finned fishes.. Our power to detect associations between jaw kinesis and transitions in feeding mode is directly connected to the sheer number of dietary transitions that have occurred in these cichlid radiations, ...
Among multigene families, ribosomal RNA (rRNA) genes are the most frequently studied and have been explored as cytogenetic markers to study the evolutionary history of karyotypes among animals and plants. In this report, we applied cytogenetic and genomic methods to investigate the organization of rRNA genes among cichlid fishes. Cichlids are a group of fishes that are of increasing scientific interest due to their rapid and convergent adaptive radiation, which has led to extensive ecological diversity. The present paper reports the cytogenetic mapping of the 5S rRNA genes from 18 South American, 22 African and one Asian species and the 18S rRNA genes from 3 African species. The data obtained were comparatively analyzed with previously published information related to the mapping of rRNA genes in cichlids. The number of 5S rRNA clusters per diploid genome ranged from 2 to 15, with the most common pattern being the presence of 2 chromosomes bearing a 5S rDNA cluster. Regarding 18S rDNA mapping, the
This study investigated the reproductive biology of Oreochromis niloticus broodstock of known age structure and spawning history with the aim of synchronising and controlling their spawning for mass fry production. Hatchery reared stock was subjected to a constant photoperiod of 12L:12D and maintained at 27 ± 1°C. All stock was fed on commercial trout pellets. The feeding frequency and protein content of the diet varied depending on fish size. Oocyte development was classified into 6 stages including that of atresia based on histology. In order to quantify ovarian maturity, three stereological methods were compared. The ovarian volume fractions of different oocyte stages estimated by the mass, graphical and intersection methods showed homogeneous results. The intersection method required less time (2.6 mins/sample) whereas the others needed 11-12 mins/sample. In addition, the numerical density technique employing the intersection method was used and yielded similar oocyte estimates to those ...
The Yellowfin Borleyi Cichlid, also known as Haplochromis barlowi, originates from the Southern part of Lake Malawi, Africa. The males have a blue body with striking yellow fins, and are one of the larger Copadichromis Cichlids reaching a maximum size of 7". When mature, the females remain brown to silver in color, and will be slightly smaller than the males. A large aquarium with plenty of caves and hiding places is ideal for the Yellowfin Borleyi Cichlid. Caves can be formed from limestone or any other type of inert rock, as well as African Driftwood. An aragonite-based substrate is recommended in order to maintain the necessary high pH and alkalinity. They do not like bright lighting, and the aragonite should ideally be either mixed with or covered by darker gravel to reduce the amount of glare in the aquarium. The Yellowfin Borleyi Cichlid requires a substrate deep enough to burrow in during breeding time. For best results in spawning, the males should be kept with at least three females. ...
Swim-up fry (average weight, 14 mg) were obtained from Oreochromis niloticus (Chitralada strain) held in concrete tanks. In experiment 1 (1985), fry were fed diets treated with 17 alpha-methyltestosterone (MT) or progesterone at 60 mg/kg for 40 days. Control fish were fed untreated diet. Fingerlings (average weight, 2.86 g) were subsequently stocked at 1/square m. in earthen ponds receiving septic tank slurry at 150 kg COD/ha/day and fine rice bran as supplementary feed for about 5 months. In experiment 2 (1986), similar procedures were followed but the fry were fed MT at 40 mg/kg for 40 days and pond stocking rates of 1,3,5 and 7 fingerlings/sq. m were compared. Individual size, sex and stage of maturity were determined. In experiment 1, the average individual size was greatest in the MT-treated group (263 g), compared with the untreated (232 g) and progesterone-treated fish (189 g). The final size of fish in experiment 2 decreased significantly (P0.05) with density, from an average of 249 g at ...
cichlids Wallpaper, wallpaper of african cichlids in an aquarium fresh water with plants and drift wook with some tetras inside too, there is also some sand, very natural looking and setting. download cichlids wallpaper for your mobile device like iphone or ipad or cell phone like a smart phone like samgung and motorolla in high definition in all sizes for free, no virus, no spam, no spyware and no malware. Share cichlids wallpaper in facebook, twitter, myspace, tumbler
And flourish it did in the Rift Valley lakes. If you were to visit these lakes, snorkel or scuba in their waters, you would most likely notice a wide variety of fish. You would not be wrong in this assessment; however, you might be surprised to find that most of these types of fish are belonging to a group called the cichlids (SICK-lids), and that all 1,650 plus species of these cichlids descended from a common ancestor. While the dates of when the common ancestor of the various cichlids came to be trapped in their respective lakes, it has been estimated that the cichlids of Lake Malawi all evolved from a common ancestor trapped 700,000 years ago, and those of Lake Victoria around 12,000 years ago. Trapped in these growing lakes while they were being formed, this small group of fish quickly came to dominate their new home, exploding in biodiversity to adapt to the wide variety of niches left open to them ...
in the mid to late 1980s. Its parentage has been highly disputed, but the most commonly speculated pairings are Midas Cichlid (Amphilophus Citrinellus) with the Redhead Cichlid (Paratheraps Synspilum). One of the more wild theories is the Severum (Heros Severus) with the Red Devil Cichlid (Amphilophus Labiatus). Blood Parrots have a round body, a beak shaped head with an upside down triangle mouth. They are often seen in bright orange in coloration, but seen in other colors such as red, yellow, brown, and tan. A further developed variety is the Convict Parrot Cichlid, which is also called the Jellybean Parrot or Bubble Gum Parrot. This is actually a double hybrid fish. It is a cross between a female hybrid Blood Parrot and a pink male Convict Cichlid Archocentrus (Cichlasoma) nigrofasciatus. Blood Parrots have reportedly been crossed with other cichlid species such as the Severum and the Texas Cichlid. So there may be other new varieties showing up down the road ...
Gante, Hugo F; Matschiner, Michael; Malmstrøm, Martin; Jakobsen, Kjetill Sigurd; Jentoft, Sissel & Salzburger, Walter (2016). Genomics of speciation and introgression in Princess cichlid fishes from Lake Tanganyika. Molecular Ecology. ISSN 0962-1083. 25(24), s 6143- 6161 . doi: 10.1111/mec.13767 Show summary How variation in the genome translates into biological diversity and new species originate has endured as the mystery of mysteries in evolutionary biology. African cichlid fishes are prime model systems to address speciation-related questions for their remarkable taxonomic and phenotypic diversity, and the possible role of gene flow in this process. Here, we capitalize on genome sequencing and phylogenomic analyses to address the relative impacts of incomplete lineage sorting, introgression and hybrid speciation in the Neolamprologus savoryi-complex (the Princess cichlids) from Lake Tanganyika. We present a time-calibrated species tree based on whole-genome sequences and provide strong ...
Well, weve had cuckoo birds on this blog before, which most people would at least have heard of, but what about the cuckoo catfish? The cuckoo catfish, Synodontis multipunctatus, a popular ornamental fish that is somewhat well-known amongst aquarium enthusiasts. It is originally from Lake Tanganyika in Africa which is hotspot of cichlid fish biodiversity. The cuckoo catfish has a rather unusual breeding habit, it is a brood parasite of mouthbrooding cichlids found in Lake Tanganyika. Just like their bird namesake, the cuckoo catfish displaces the legitimate offspring of its host, forcing the cichlid to rear its young, and they have a rather clever way of accomplishing this. The catfish is attracted by the scent of the brooding cichlids, and as soon as they detect any such brooding cichlid in the vicinity, they race to the scene of the coupling. The catfish mob the pair of spawning cichlids and as soon as their eggs are fertilised, a mating pair of cuckoo catfish dash in, the female laying her ...
Dr. Russell Fernald is a neuroethologist at Stanford University. Neuroethology integrates brain science with the study of behavior in natural habitats. The goal is to illustrate the interaction among brain, behavior, and environment. Dr. Fernalds long-term work focuses on the African cichlid fish and how its social system regulates not only brain structures, but also bodily functions.. When a male cichlid fish recognizes an opportunity to become the dominant male, his body turns bright colors. The male fish then chases and attacks other male cichlid fish in an attempt to dominate and defend his territory. The physiological color change results from a response in the hypothalamus in the brain. In the cichlid fish, the signaling peptide cells grow eight times larger, sending the brain eight times the signal. The result is an enlargement of the fish gonads, physiologically preparing the fish to spawn with females.. When the cichlid fish loses control of the territory, he loses his bright coloring. ...
For the first time, scientists have directly linked social cues to an immediate genetic response in the brain, according to a new study in PloS Biology. Only minutes after subordinate male cichlid fish sense an opportunity to become socially dominant, they display dominant characteristics such as changes in color and behavior, and express egr-1, encoding a transcription factor that likely triggers enhanced fertility and other long-term dominance traits.. "People forget that social influences are pretty important," said study co-author Russell Fernald at Stanford University in California. "Heres the case where the social is everything. [It] regulates brain structure in a very direct way.". Characterized by a dynamic social hierarchy, the cichlid fish Astatotilapia (Haplochromis) burtoni can readily alter sexual capacities, and only dominant males are physiologically able to reproduce. "We were interested in understanding how this occurred at a mechanistic level, uncovering earliest steps that ...
The Albino Peacock Cichlid comes from the rocky, sandy shores of Lake Malawi, Africa. They are pale in coloration and their eyes are red. The coloration of the male and female are very similar, and the male displays the typical egg spots on the anal fin. The Albino Peacock Cichlid does well in an aquarium that is at least 50 gallons with plenty of rocks for territories and a sandy bottom. The males are usually only aggressive towards their own species unless their territory is invaded upon. Provide a ratio of 3 to 4 females to one male. Again, provide multiple females for the male, as it will take the stress off of the female carrying the eggs. Incubation is approximately three weeks, at which time the female will release the fry. Provide the fry with newly hatched brine shrimp and finely ground flake food. The Albino Peacock Cichlid should be fed a variety of both meaty and vegetable-based foods. Feed live and frozen brine shrimp along with Spirulina-based flake and pellet foods. Approximate ...
Phenotypic differences may have genetic and plastic components. Here, we investigated the contributions of both for differences in body shape in two species of Lake Malawi cichlids using wild-caught specimens and a common garden experiment. We further hybridized the two species to investigate the mode of gene action influencing body shape differences and to examine the potential for transgressive segregation. We found that body shape differences between the two species observed in the field are maintained after more than 10 generations in a standardized environment. Nonetheless, both species experienced similar changes in the laboratory environment. Our hybrid cross experiment confirmed that substantial variation in body shape appears to be genetically determined. The data further suggest that the underlying mode of gene action is complex and cannot be explained by simple additive or additive-dominance models. Transgressive phenotypes were found in the hybrid generations, as hybrids occupied ...
Accumulation of some heavy metals (copper, iron, manganese, nickel and zinc) and its effect on the hematological indices on the freshwater fish (Oreochromis niloticus) were studied. Fish Samples were collected from the River Nile near El- Kanater El-Khyria and contaminated water from Iron and Steel Basin in El-Safe Village near Helwan, south of Cairo. Results of this study showed that there was a significant difference between the water qualities indices among the two different locations. Meanwhile, fish samples that collected from polluted location showed high values for the hematological indices namely hemoglobin (Hb), red blood count (RBC), hematocrit (Hct), white blood cell count (WBC) and erythrocyte. Moreover, the concentrations of heavy metals were also high in the fish. However, the levels ofthe heavy metal accumulation were within the maximum permissible limit for human consumption (FAO, 1992). The order of bioaccumulation of such metals in the liver of fish were Fe | Zn| Cu | Mn | Ni. It was
Identifikasi bakteri patogen pada ikan Nila (Oreochromis niloticus) di lokasi budidaya ikan air tawar Kabupaten Kepulauan Sangihe
Researchers have discovered that a form of oxytocin-the hormone responsible for making humans fall in love-has a similar effect on fish, suggesting it is a key regulator of social behavior that has evolved and endured since ancient times.. The findings, published in the latest edition of the journal Animal Behaviour, help answer an important evolutionary question: why do some species develop complex social behaviors while others spend much of their lives alone?. "We know how this hormone affects humans," explains Adam Reddon, lead researcher and a graduate student in the Department of Psychology, Neuroscience & Behaviour at McMaster University. "It is related to love, monogamy, even risky behaviour, but much less is known about its effects on fish.". Specifically, researchers examined the cichlid fish Neolamprologus pulcher, a highly social species found in Lake Tanganyika in Africa.. These cichlids are unusual because they form permanent hierarchical social groups made up of a dominant breeding ...
Lyretail Cichlid Photos, Neolamprologus brichardi Photos, Lyretail Cichlid Pictures and Photographs by Professional Natural History Photographer Phillip Colla / Oceanlight.com
Dopamine regulates reproduction in part by modulating neuronal activity within the hypothalamic-pituitary-gonadal (HPG) axis. Previous studies suggested numerous mechanisms by which dopamine exerts inhibitory control over the HPG axis, ultimately changing the levels of sex steroids that regulate reproductive behaviors. However, it is not known whether these mechanisms are conserved across vertebrate species. In particular, it is unknown whether mechanisms underlying dopaminergic control of reproduction are shared between mammals and teleost fish. In mammals, dopamine directly inhibits GnRH1 hypothalamic neurons, the gatekeepers for activation of the HPG axis. Here, we demonstrate, for the first time in teleost fish, dopaminergic control of GnRH1 neurons via direct dopamine receptor type-2 (D2R) mediated inhibition within the hypothalamus. These results suggest that direct dopaminergic control of GnRH1 neurons via interactions in the hypothalamus is not exclusive to tetrapod reproductive control, ...