I explained to my stepbrother why housing the angelfish, the goldfish, and the pleco together in the 10-gallon was not a wise aquarium setup and he completely understood. Apparently it was what was suggested to him by the Petco employee (!?!?!??) when he picked out the 10-gallon tank. He’s looking into purchasing a larger tank (I believe he mentioned getting a 20 or a 29 gallon), however I’m not sure that he understands the pleco needs to go or that the angelfish and goldie are incompatible species…I’m not great at being blunt. He is sincerely trying to do what he can to amend the situation though, and I think that that is admirable and responsible so I’m proud of him.