Is my 55g tank overstocked?

Dec 1, 2013
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#21
Initially, I thought he a Jack Dempsey as well, however I bought him as a jewel cichild. All my fish in the tank are at their matured size, and he has stopped growing. So I'm at a loss of what he is. I thought he might be a hybrid or something. Anyways, thank you for clearing up the other fish! That helped a ton!