I have a diamond watchman goby that Ive had for about 4 months. He wont eat anything I feed just what he can get out of the sand which isnt very much since I also have a pink cuke in the tank. He's gotten really skinny and I am getting worried about him. Should I put the cuke in another tank so theres more food. Can I bury food in the sand and hope he finds it? What should I do.