Kuda....
Both of the fish in the previous post are Polypterus senegalus. Unfortunately what your LFS sold you as Polypterus palmas really isn't one.
P. senegalus undergoes a considerable change in pattern from baby to young adult. The babies have longitudinal stripes that gradually disappear as the fish grows until they finally are completely gone (or represented by only a series of small black dots). The adult coloration, of course, is an overall grayish or brownish color with no distinctive pattern.
-Joe