Over the last few decades a picture has been coming into focus that our corals are so much more than one simple animal, but a whole ecosystem unto themselves. Both the solitary and colonial coral species that we keep in our aquariums are mostly photosynthetic with algae living inside of their cells, but there’s whole other layer of living critters and microbes living with our corals.
The list of organisms associated with corals range from the tiny that live on the surface, macro invertebrates such as mussels and crabs that live in the skeleton or among the branches, not to mention a whole suite of pests and parasites that makes our reef lives such a pain. Over the years we’ve documented a wide range of uninvited coral critters including ctenophores, crabs, ciliates, hydroids, snails, nudibranch, flatworms – many of which are most common on one group of corals.
But a new study published in Reviews in Aquaculture titled “Parasites and coral-associated invertebrates that impact coral health” is a pretty comprehensive review of things that live on our corals, and how corals feel about it. The paper is a pretty hefty read and probably not very enlightening for the casual hobbyist, but any professional coral handler and especially the coral farmers should really make time to at least give it a glance.
One of our ‘favorite’ coral parasites this paper reminded us of is a kind of flatworm called a trematode that encysts itself in Porites corals causing bright pink bumps and nodules. There’s still a lot of coral ‘maladies’ that we’ve yet to ascribe to any particular purpose, corals don’t just die or suffer without a reason, but even the most experienced of us are guilty of not tracking down every single cause.