Fifteen behavioral measurements were taken on paradise fish of two inbred progenitor strains and of 16 recombinant lines derived from their cross and maintained under inbreeding with gynogenesis and sib-mating. Univariate and multivariate analyses showed significant differences among the RI means on all measures. Four combined variables extracted by principal component analysis showed that there were common sources of a large part of the behavioral variability measured in the arbitrarily designed test situations. There were no separate subgroups of the RI strain means, and overlapping ranges point to a polygenic genetic determination of the studied behavioral phenotypes. A biometrical analysis of the distribution pattern of recombinant lines and the progenitor strains showed that in several characters non-allelic genic interactions made a significant contribution to the variation. Additive and interaction components of the mean, the heritabilities and the minimum number of effective factors were estimated for all studied behavioral phenotypes, and the combined variables as well.