Hiya erik and welcome to MFK, if your fish is small now you have a while to make arrangements, I had a friend who would grow out large fish to around 18" (the largest he could keep) then donate them to Public aquariums and schools, the trick is to make the arrangements well in advance. Like now, submit pictures and a species profile along with an estimate of when the fish would be ready, include genus/species, species origin area, and where you got it, as well as species parameters. Given enough lead time many aquariums are happy to get unusual specimens but they need time to evaluate if they have a place for it. Most people who try to give institutions fish wait until the last minute and the aquarium has no suitable accomodations. Even if they can't take it they might be able to steer you to who can.