In the fish farms here in Brazil, they use this kind of pellets only to grow out fish that will be killed and sold as food. The fish , mostly big guys like Pirarucu( arapaima gigas) and Sorubim ( TSN), stay in the farm for a period of 1 year max. During this time, they feed them with this super caloric pellets. It really makes the fish get real big and fat, but i dont think is good for the fish in a long term. Its like feeding them McDonalds everyday. So, for aquaria purposes, its not a good idea, i guess.