A Comparative Analysis of the Preference for Dark Environments in Five Teleosts
Abstract
The present article tried to establish dark/light preference in five different species of teleosts. We proposed, using the data obtained with this method in zebrafishes ( Danio rerio ), Cardinal-tetras ( Paracheirodon axelrodi ), lambaris ( Astyanax altiparanae ), Nile tilapias ( Oreochromis niloticus ), guppies ( Poecilia reticulata ) and banded-knife fishes ( Gymnotus carapo ), that preference for dark environments is a reliable and low-cost index of anxiety/fear in those species. A scototactic pattern of exploration was found in all species, and the pattern of locomotion in the white environment suggests its aversiveness for those species, with the exception of G. carapo and O. niloticu s. A comparative analysis uncovered species differences in approach-avoidance dimensions of the task. The data are discussed in terms of the behavioral ecology of the animals and prey-predator relationships, suggesting a link with predator defense strategies in teleost.