When my res's were babies (around the size of a quarter) I fed them zoomeds juvenile pellets. The rule of thumb is to feed them an amount equivalent to the size of their heads. You can also float romaine, steamed carrots, and other veggies in the tank but at this age they are pretty much carnivorous and may not eat veggies until they are older. Try small amounts of krill every so often but don't give them too much protein. I also started floating very small pieces of cuttlebone at this age to give them more calcium. I'm sure that you've given them all of the other info that they need like heat, basking spot, uvb/uva lights and all of the other stuff.