SPS eating Nudibranch

[blane perun]

I inadvertently acquired a pesky predator to my system last year, the Aeolid Nudibranch.
The Aeolid belongs to the suborder Aeolidoidea, and is very unique amongst other Nudibranch relative to its defense mechanism. The Nudibranch consumes SPS and actually separates these stinging cells within its digestive track. Interestingly the stinging cells (nematocysts) are not digested at all, but relocated to the tips of its extremities. Perhaps because of this there seems to be no know biological control. Reading some post on the boards led me to a Tracy Gray whom has had a previous published article on dealing with the pests. Applying Tracy’s method of defense (Tetra Oomed) I was not able to kill off the predator. In later conversations Tracy shared that the method had initially appeared to work, but in the long run noticed it had failed. I found no means of irradiating the Nudibranch’s from the system other than a slow tedious manual process. I did however slow (if not temporarily halt the reproductive cycle) by dropping the temperature of the system for 80 to 74 degrees and lowering the salinity from 1.024 to
1.0185. The amount of newly deposited egg sacs seemed to stop all together and I went through the long process of dipping infected colonies in a fresh water solution.

[Ninong]

Blane,

Did you notice which SPS corals in particular were being attacked in your tank? Most Aeolids are specialists that feed on a specific genus. However, they do not feed on SPS exclusively. In general, Aeolids feed on hard corals, soft corals, sea anemones and hydroids. Basically anything they can harvest nematocysts from.

Did you experience any problems with any of the beneficial inhabitants of your tank when you lowered your salinity to 1.0185 from 1.024 and how quickly did you make this adjustment?

BTW, not all Aeolids are bad guys. Berghia verrucicornis is a good Aeolid that eats only Aiptasia spp. anemones.

Aeolids and Dorids are the two largest suborders of Nudibranchia. It's possible to refer to any members of the suborder Aeolidina (Aeolidoidea) as Aeolids but most people use the term Aeolid in reference to members of the Family Aeolidiidae. There is more than one family in that suborder. I'm not sure exactly how many different genera and species there are, but it is a large number.

This is the taxonomy of B. verrucicornis as an example:


Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Opisthobranchia
Order: Nudibranchia
Suborder: Aeolidina (or Aeolidoidea)
Family: Aeolidiidae
Genus: Berghia
Species: verrucicornis