It just takes a lot of feeding. Mine look like that when I feed them every 2 days vs 1-2 times a week. I should start mine back on their 2 day diet. I throw a mxture of Mysis, Cyclopeeze, and silversides, sometimes mixed with some spirulina pellets I ground up. They love getting fed, Mine will eat about 2-3 cubes worth of mysis, 1 cubes worth of Cyclopeeze, and about half a silverside. Mine are always hungry and ready to open for feeding, took me about 2 weeks to train them that way.
Peef, good job though, I know it isn't easy.