That is my treasure fish in there,my flowerhorn(already starting to grow a kok) It's 4-6 inches about. and if the severums and parrots are big enough then they will be fine! i have two parrots in there with it the flowerhorn is aressive for food but when full they are really nice.It eats out oof my hand and takes various food. very fun fish to own.very nice fish!!! whats that big fish in the front, the first big one who comes to the frint? I love that fish !! whats he called and is he agressive? will he go with parrots and sevrums etc?