Somatic chromosomes from the kidneys of both sexes ofAplocheilus panchax(Cyprinodontidae), of maleLates calcerifer(Percidae) and germinal chromosomes from the testes ofA. panchaxandGadusia chapra(Clupeidae) are described. In both sexes ofA. panchax, the somatic complements consist of 38 chromosomes, measuring between 2.6 and 1.1 μm in male and 2.7 and 1.1 μm in female. The male karyotype comprises 7 pairs of metacentric, 4 pairs of submetacentric, 2 pairs of subtelocentric and 6 pairs of telocentric chromosomes. The female karyotype differs in having one fairly large submetacentric more and small metacentric less than the male karyotype indicating thereby female heterogamety (ZW) in this species. The spermatocytic metaphase I contained 19 apparently homomorphic bivalents.L. calcerifercontains 2n=48 chromosomes which can be aligned into 24 homomorphic pairs comprising 1 pair of metacentric, 3 pairs of submetacentric, 1 pair of subtelocentric and 19 pairs of telocentric chromosomes. The chromosomes range between 2.4 and 0.9 μm in length.G. chaprahas in its spermatogonial metaphases 2n=46 rods measuring between 2.3 and 1.0 μm. 23 homomorphic bivalents with terminalized chiasmata are found in primary spermatocytic metaphases. Sex elements are not recognizable in males ofL. calceriferandG. chapra.