If you like the damsel you can also rearrange the rockwork when you add other fish. But back on topic, don't worry about him getting the food, he'll find it. Ask the store where you got it from what they feed. This will be the easiest food to get him to take. For future reference make the store feed the fish before you purchase it. This way you know what it eats as well that it is eating. I would suggest Spectrum pellet food. It seems to be the favorite of all my fish meat eaters and plant eaters alike. I also feed nori, frozen bloodworms, and frozen mysis every few days for variety.