The results obtained using morphometric variables which describe fin ray regeneration patterns are reported for individual fin ray amputations in the goldfish (Carassius auratus) and zebrafish (Brachydanio rerio). Classical and updated experiments are compared to verify previous morphogenetic models of cell tractions (Oster et al. 1983) or epidermis-mesenchyme induction (Saunders et al. 1959) applied to the limb of other vertebrates. Position-dependent patterns within the fin of Carassius auratus are analysed under a comparative protocol using morphometric methods. Conditions in which the apical epidermis is separated from blastema may differentiate small fin rays, thus suggesting this epidermis is involved in blastemal formation. Blastemal cells differentiating as lepidotrichia forming cells (LFCs) may also be related to morphological changes in covering epidermis. Long-range interactions from neighbouring fin ray blastemas or short-range interactions within the blastema, may be postulated through the analysis of segmentation.