Have you ever noticed that the majority of Anemonefish in Lembeh have tongue-biting isopods in their mouth? Most of the isopods are so small they are hardly noticeable. This week, however, this large, female Cheek-Spine Anemonefish put on quite the show as she gaped at divers, showing off her over-sized creepy critter.
The “Tongue-Biter Cymathoid Isopod” is a commensal isopod, meaning it lives on its host Anemonefish and benefits from the situation, but at no harm to the host. It makes its way into the Anemonefish’s mouth via the gill slits at a very young age, settling onto the fish’s tongue. The tongue atrophies under the isopod, eventually being entirely replaced by the small animal. Once settled into its new home, the isopod is assured of a good meal any time the Anemonefish feeds. The Anemonefish does not benefit from the isopod’s presence (obviously!), but surprisingly it is not negatively affected either, save for a bit of early stage, awkward jaw-growth that creates space for the isopod.
If you are interested in seeing one of these kooky Lembeh critters next time you are diving with us, make sure and let us know! But if isopods don’t pique your interest, never fear: we also saw plenty of Wunderpus Octopus this week, along with a gaggle of Ambon Scorpionfish, beautiful little Emperor Shrimp hanging out on a variety of Nudibranch, many Ocellated Tozeuma Shrimp, the ever-present Frogfish, and even a few crowd-pleasing Pom-Pom Crabs.
***This week’s lesson: You might want to think twice before you take you regulator out of your mouth when you are diving in Lembeh: you might just end up going home with an extra critter-souvenir!***