We investigated chemical cues among groups of zebrafish (Danio rerio) when communicating information about the risk of predation. We found that visual cues of the predator (tiger Oscar, Astronotus ocellatus) did not increase whole-body cortisol levels in groups of zebrafish but that water conditioned by these (donor) zebrafish stressed (target) conspecifics, thereby increasing whole-body cortis...

The efficacy of [3-H]proline radioautography for tracing retinal ganglion cell projections to the optic tectum of the jewel fish, Hemichromis bimaculatus, has been compared with that of degeneration techniques. There was good agreement between the various methods. Retinal projections to the optic tectum of two other teleosts, the oscar, Astronotus ocellatus, and the goldfish, Carrasius auratus,...

Nephrocalcinosis is a chronic disorder which may be resulted in decrease in growth rate and finally mortality in severe condition. Nephrocalcinosis is defined as the presence of calcification in the kidney. A total number of 80 ornamental fishes of different species included of discus fish (Symphysodon discus), angelfish (Pterohyllum sp.), goldfish (Carassius auratus) and oscar fish (Astronotus...

We tested the effect of social isolation on the aggressiveness of an Amazonian fish: Astronotus ocellatus. Ten juvenile fishes were transferred from a group aquarium (60 x 60 x 40 cm) containing 15 individuals (without distinguishing sex) to an isolation aquarium (50 x 40 x 40 cm). Aggressiveness was tested by means of attacks on and displays toward the mirror image. The behavior was video-reco...

At Chapel Hill, Chapel Hill, North Carolina; Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Sistemas Locales de Atención Integral a la Salud, León (SILAIS-León), Leon, Nicaragua; Hospital Escuela Oscar Danilo Rosales Argüello (HEODRA), León, Nicaragua, Leon, Nicaragua; Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill...

JOHN D. MCVAY*, OSCAR FLORES-VILLELA and BRYAN CARSTENS Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA Facultad de Ciencias, Museo de Zoologia, Universidad Nacional Autonoma de Mexico, Circuito Extrior de CU, Mexico, DF, 04510, Mexico Department of Evolution, Ecology and Organismal Biology, The Ohio State University, 318 W. 12th Avenue, Columbus, OH, ...