I feed my yellow labs three foods: normal fish flakes, spirolina flakes and a mix of brine shrimp and blood worms (frozen and thawed). I think this is the best way to go since they can get everything they may need. I also never scrape or remove algea from the back of my tank (not that there is alot anyways, but...) because they love it. I also use the flake foods most often and the frozen foods once weekly. The spirolina flakes seem to sink pretty fast, so I feed slowly. I also have used cichlid pellets or sticks with good results in place of the normal flakes. My fish are sort of inbetween sizes right now as far as those pellets or sticks go and so I am waiting for them to get big enough for the large sized ones.