Can I return fish to the shop once they get too large?

What do you think the shop is going to do with them? The bulk of large fish are fast growing if given enough space, so other than some specific situations then large fish aren’t wanted by the shop or other keepers.

There are some cases as I said, the main ones being where keepers want to add a larger specimen to an established group, where smaller ones might get attacked or bullied otherwise. But we’re not talking about common plecs, pangs, bala sharks and the like here. When I’m after a breeding pair of certain cichlids I may buy 6 youngsters and grow them on until a pair forms. The others then will be offered for sale to other keepers, on occasion the shop I bought them from has bought the other 4 back, in this case the shop knows they can sell on these fish.

Talk to the shop, is it worth them buying the fish back from you, do you have a grow out tank set up for them, or are you buying a tank buster that no one will want as an adult?

We have thousands of different fish available to purchase, surely you can find something that will thrive in your tank for it’s entire life?