You can mix it up a bit and feed frozen fish, shrimp, squid and scallops.
Crickets and mealworms are good occasionally, but can be addictive, so i feed them only as treats. For frozen foods my guy likes prawn (stuffed with pellets) and squid the best, along with freeze dried krill.
And, mine is in a 6 X 2 X 2, and its pushing it for space.