6533b86cfe1ef96bd12c7f4b

RESEARCH PRODUCT

Social control of testicular steroidogenic capacities in the Siamese fighting fishBetta splendens Regan

subject

description

Male Siamese fighting fish (Betta splendens Regan) of the veiltail variety were raised. At the age of 4 ½ months they were either isolated or community-housed for 2 ½ months. After that time the relative fin lengths were determined, and the in vitro metabolism of testosterone by the testes of the fishes was investigated. Community-housed specimens had shorter fins than the isolated males. Their testes formed less 11-oxy- and more 5β-steroids than those of the isolated males. This difference was even larger when high- and low-ranking community-based specimens were compared. The appearance of low-ranking males resembled that of females, and the main products of their testes were 5β-reduced steroids. These results are interpreted as evidence for a social control of steroid metabolism and hence reproductive ability in the fighting fish.