I have noted that in at least one case, tetras will school with a
similar species. I have 6 Cardinal tetras and 6 neon tetras in my 29
gal planted tank. While the fish will disperse when relaxed, when
they school as they do when started by one of the cats or something
else, both will school together in one 12 member group. I've even
seen the two species display to each other, so I suspect that the
'see' the other kind of tetra as a sort of relative, even if the color
patterns and frequencies are different.

Mike K wrote in message ...
I have a 55 gallon tank that I'm just getting ready to stock with fish. If I
stock with 8 cardinal tetras, 8 glo light tetras and 8 penguin tetras
(amongst other species) will the tetras all school together or will they
stick with their own kind (ie: cardinals with cardinals, glo lights with glo
lights and penguin with penguin)?