Polyploidization is thought to be an important driving force in evolution as it increases the genetic material on which mutation and selection can act. In the Amazon molly, Poecilia formosa, triploid genotypes can be found in the field and frequently arise from diploid breeding stocks, a tetraploid individual, however, was so far never documented. Here, we report the first tetraploid Amazon mol...

Acute toxicity tests were performed over a period of 120 hours using different concentrations of effluent of treated rubber wood processing wastewater on freshwater fish, Poecilia reticulata. The LC50 values of the effluent exposed to P. reticulata for 24, 48, 72, 96 and 120 hours were 19.77, 19.55, 19.25, 18.99 and 18.75 ml/dl respectively. Mortality was observed in a dose dependant manner. Th...

Aim: To consider how geographic variation in species recognition over time affects the speciation process. Organisms: The gynogenetic livebearing fish Poecilia formosa (Amazon molly) is the hybrid offspring of two bisexual parent species, P. latipinna (sailfin molly) and P. mexicana (Atlantic molly). The Amazon molly is an all-female species that must mate with males of their parent species. Bu...

In the present work Trichodina reticulata and T. nobilis (Ciliophora: Trichodinidae) are morphologically characterised from ornamental freshwater fish culture in the State of Santa Catarina, Brazil. The prevalence of infection and a list of comparative measurements are discussed. We examined "southern platyfish" Xiphophorus maculatus (n = 35), "goldfish" Carassius auratus (n = 31), "guppy" Poec...

Parasitic diseases are harmful and limiting factors in breeding and rearing ornamental fish industry. In this study, 400 apparently healthy ornamental fishes from five species (each species 80 specimens) including: Goldfish (Carassius auratus), guppy (Poecilia reticulate), angelfish (Pterophyllum scalare), discus (Symphsodon discus) and sailfin mollies (Poecilia latipinna) was obtained from a l...

Regressive evolution of structures associated with vision in cave-dwelling organisms is the focus of intense research. Most work has focused on differences between extreme visual phenotypes: sighted, surface animals and their completely blind, cave-dwelling counterparts. We suggest that troglodytic systems, comprising multiple populations that vary along a gradient of visual function, may prove...

BACKGROUND Grouping behaviour, common across the animal kingdom, is known to reduce an individual's risk of predation; particularly through dilution of individual risk and predator confusion (predator inability to single out an individual for attack). Theory predicts greater risk of predation to individuals more conspicuous to predators by difference in appearance from the group (the 'oddity' e...