Cold temperature tolerance of albino rainbow shark (Epalzeorhynchos frenatum), a tropical fish with transgenic application in the ornamental aquarium trade

Abstract

Application of fluorescent protein transgenesis has commercial use for the ornamental aquarium trade by creating new colour phenotypes in various species. To determine the potential for transgenic ornamental aquarium fish to overwinter in Canada, the minimum temperature tolerance of albino rainbow shark (Epalzeorhynchos frenatum (Fowler, 1934)) was estimated to complement a previous study examining cold tolerance of zebrafish (Danio rerio (Hamilton, 1822)), black tetra (Gymnocorymbus ternetzi (Boulenger, 1895)), and tiger barb (Puntius tetrazona (Bleeker, 1855)). Rainbow shark had higher low temperature tolerance limits (LD50 = 10.7 ± 0.1 °C) than surveyed winter water temperatures in Canada. There was a significant negative correlation between condition factor and temperature at loss of equilibrium, suggesting fish with lower social status may be more susceptible to cold temperature than dominant fish. These results indicate transgenic E. frenatum are not expected to persist over winter in Canadian waters.