RES can be trained to take pellets, particularly sinking ones, but they are far harder to train than are BG. Their is anecdotal evidence suggesting that RES help control parasites. This is because RES will eat snails which are a secondary host to yellow grub and other similar fish parasites that are spread, usually through fish eating birds like herons and king fishers. Waterfowl may also spread parasites as well. There is lots of good information on the forum are cage culture of BG and RES. Check the archives or do a search or perhaps ewest can point you in the right direction as to where such info can be found...