Hello folks, Gary, I have noticed that for my nijsseni, the dark caudal spot can take up most of the caudal peduncle (the area just before the caudal fin) but does not seem to extend into the caudal fin itself (male or female). In contrast, the pandurini caudal "spot" does extend into the caudal fin. By the way, you are definitely convincing me that your male could be unique-sounds like you have a lot more experience with these things than I do! Simon wanted to know when his D. filamentosus (and I believe this list should be supportive of all types of dwarf cichlids) would start to show some sexual dimoprhism. I have bought them at about 1" and I really didn't see the beginnings of tail fin extensions (male) until they were at least 1 1/2 " (5-6 cm), in some cases even larger. I was actually lucky enough to get mine to spawn for me, and I now have 10 fry ranging from about 1/2"-3/4" (I gave 6 away to someone really good, just to be safe). I am hoping the size difference means I have both sexes, but when I can first tell, I will let you know. Oh yeah, as soon as I moved the two pairs of adults out of their tank, they all died. I'm sure they spawned for me because they just knew they faced imminent death. One last question- does anyone have A. piauiensis, and can they easily tell the sexes apart? At one point I had seven in a tank, and I was really having a hard time trying to sex them (I just gave 2 away, and the person I gave them too was also having problems). Not one consistently looks like the male piau shown in the Aqualog book (the only pictures I have seen). I am monitoring their ventral & dorsal fins, but if anyone has a better suggestion please let me know. Thanks alot, Lisa