Ethological analysis of social and environmental effects on the distribution of the behavioural elements of the paradise fish (Macropodus opercularis L.).

The behaviour of the paradise fish in a new environment was examined. The influence of space, the number of conspecifics, the number of each sex in the various groups and the time allowed for habituation on the distribution of various behavioural elements were revealed. By means of principal component analysis five biologically meaningful factors were extracted. Using the scores of the various factors as indices of settlement, fear passive behaviours and exploration, special effects of the environment were assessed. In small tanks the fish are in an emotionally low but stable continuously trying to escape. Being prevented from escaping they develop various passive behaviour forms which alternate with escape. In a large tank the main occupation of a female fish on its own is exploration at the start; this is accompanied by a fearful state. In groups of four the activity of exploration is less and the fearful state is not so pronounced. The presence of males seems to secure the most stable state in a new environment though after about two days the males start breeding activities and this involves a new spectrum of activities.