Looks like a male convict juvenile (Amatitlania nigrofasciata). And my guess is you bought it on shipment day. I stop through my LFS weekly to see if anything catches my eye, and I commonly see these guys thrown into the same tank as the "assorted peacocks"
They're pretty hard to find..you may get some chances at pet smart or Petco..but sometimes they're too small to sex..jay said most of them don't survive shipping very well..
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