From Advanced Aquarist.....
Copepods, amphipods, isopods, ostracods:
Certain species are parasitic and predatory. Some may form galls in coral tissue and may or may not be true parasites like the gall crabs. Many are merely commensal, living on coral mucus and associated flora and fauna. As such, they may be performing a cleaning function.
Hyperia galba amphipod predatory to coral tissue
Paramphiascopsis sp. parasitizes from a pocket formed in the tissue of gorgonians
Paramolgus antillianus associated with Ricordea florida
Acontiophorus bracatus ectoparasite of gorgonians, Leptogorgia, Eunicella and Paraerythropodium spp.
Asteropontius corallophilus parasite of Pocillopora, Montipora, Stylophora and Porites spp.
Asteropontius longipalpus associated with Ricordea florida
Asterocheres scutatus parasite of Rhodactis rhodostoma
Lichomologus spp. 6 species parasitic to octocorals, 3 species to fungiids, 7species to octocorals and stony corals, 5 species withPalythoa spp., 2 species with Rhodactis spp., 2 species with Psammocora spp. , 10 species to stony corals.
Acanthomolgus spp. 4 species parasitic to Atlantic gorgonians, often species specific
Psuedanthessiids spp. true parasites for all species in this genus
Rynchomolgids spp. true parasites for all species in this genus
Notodelphyids spp. some true parasites of octocorals, Paraerythropodium sp.
Xarfia spp. copepods with worm-like bodies and reduced legs that are parasitic and live inside coral polyps.