[Zoaelite]

Aquarists who like to grow macroalgae should be aware that some pygmy angels might devour their crop. One species that seems to be particularly fond of Caulerpa shoots is the flame angel (C. loricula). Several species also feed heavily on the feces of other fish. For example, the Japanese pygmy angelfish (C. interrupta) associates with schools of lyretail anthias (Pseudanthias squamipinnis) and planktivorous damselfishes to feed on their fecal material. In the aquarium, I have seen a number of pygmy angelfish engage in this feeding mode, known as coprophagy.

http://www.fishchannel.com/saltwater...my-angels.aspx