I have these two catfish, mao and yui. :o Today was the day of the week where I don't feed them, and I noticed yui (the smaller talking catfish) was nipping(?/it looked like nipping) at mao (little bigger humbug catfish). Well mao did have a pretty full stomache compared to yui, but I didn't underst...

:d the flat fish with the black stripes is a Black Tetra.
:o the other fish is a...
XD it kind of looks like a Spotted Pimelodus (a kind of catfish)
...and maybe the catfish that died was sick from the pet store.
(were there any dead fishes in the tank he was in at the pet store?)