For me a big tank clown loach would be the first on the list. I'm being serious here, before you start putting in your big shoals of fish you should do a project of getting 2 huge 12"+ matured clown loach male + female and try and get them to breed and do an experiment on how they react in certain conditions like after a water change. There have been reports before of breeding but you could be the one who is successful and reports it. It will be wicked if you were to breed clown since it has never been done, meaning reported in.
Then you can start your shoaling community project. I'm just dreaming while i'm typing lol.