There also is Hikara Mega Marine Angel, that also has sponge, but I like the Ocean Nutrition stuff, pictured above, better. It has slightly better nutrition percentage, and it sinks instead of floating like the Hikari stuff.
In addition to the sponge-based food, the Angel will also need algae, dried seaweed sheets on the clip is usually the easiest, and some meaty foods, clams, scallops, squid, etc.