Provide plenty of other hiding places in a 125 gallon tank or larger as the Flagfin Angelfish is quite shy early on and should be the only angel in the tank. Not a good reef dweller, the Flagfin Angelfish is prone to nip at sessile invertebrates (soft and stony corals) and clam mantles.
This is a difficult angelfish to keep due to its dietary requirement of sponges and its poor ability to adapt to other foods. Expert aquarists may have success by providing a mixed fare of sponge-containing frozen angelfish rations, vitamin-enriched brine shrimp, mysis shrimp, a plethora of plant material, and live rock for grazing and hiding. (thank you to alive aquaria for this information)