I don't have one, but oscars, commom plecos, and bala sharks are like standard fish always available in the big box stores. There is no information on them so everyone buys one or five, regardless of the size of the tank. Then I think that oscars and common plecos are pretty hardy so survive and then some (very few if you think about it) are rehomed. I think bala sharks are more sensitive and probably die of stress, glass banging, or jumping out of tanks so you don't see them rehomed as often. I also think many of these three, the vast majority, as well as other species (green terrors come to mind) die or are euthanized.
Sad. Big box stores should not be this lame.