Tuna, blowfish, football fish, koi, rainbow trout, jewel beetles, miyama stags, and emperor butterfies are unnecessary in the game. I've leveled campers' friendship up to max level 20 and they do not ask for these items. I just sell them in game. I hate it when people put these things in their market boxes because no one is ever going to buy them and when you're looking for something useful, like fruit, and keep seeing these useless rare items for ridiculous prices, it's a waste. I delete these people from my friend list. We can only have 100 friends so I don't bother with the folks that put ultra rares in their boxes.
Sell your tuna in game for 5,000 bells.
Campers DO ask for horned dynastids, black bass and red snapper.