It's the Watchman goby - white with yellow spots. It usually is on the sandbed piling up hills of sand. I have cut back on feeding to lower nitrates. He does grab mysis shrimp, seaweed, etc. He's just scared of me so runs away when I feed. I think maybe cutting back on food has left him out of the feeding frenzy. Touch balance to not overfeed, yet make sure everything gets food. I did put some shrimp pellets in today for him....