This attractive little nudibranch is so far known only from Enewetak Atoll, where it is relatively uncommon. It is quite similar to and probably closely related to Goniobranchus rubrocornutus, which has not been found at Ewewetak but does occur in other Marshall Islands atolls. Most of the specimens observed were on lagoon interisland reefs under chunks of dead coral or aluminum storm debris at depths of 3 to 5 meters. A few were found on lagoon pinnacles as deep as about 15 meters. The largest of 26 measured specimens was about 26mm, although I have photos of a couple of others that probably exceeded 30mm. Goniobranchus galactos was first reported in the Marshalls from Enewetak Atoll by Rudman (1985).
This nudibranch eats the pink sponge in the photo below.
Created 14 December 2005
Updated 1 July 2012