It really is an open secret that here at ReefBuilders, we are head over heels for Plectranthias. It is hands down one of the coolest genus of fish for the home aquarium. They’re charismatic and shy at the same time, don’t get too big, add tons of mystery and charm to aquariums of all sizes, and they look amazing. The only heartbreaker for this genus is that with the exception of P. inermis, all can be considered rare, and most of the time very expensive as well.
The genus is big, with many species available with varying difficulty in the trade both described and undescribed – a topic we will touch on soon. Unfortunately, all are either very rare like P. nanus and P. fourmanoiri, or very rare and expensive like P. sagamiensis, P. garrupellus, and various other undescribed species that hit the japanese market ever so scarcely. P. pelicieri used to belong to the latter group, but in recent years have become more obtainable as well as affordable. However it is still relatively expensive, hovering around the $1,000 price tag.
The only outlier of this genus that is both common and cheap, is Plectranthias inermis. Also known as the Geometric perchlet, this species is always available in the market and costs only a few tens of dollars. P. inermis is a great beginner fish that is suitable for all tank sizes, even nano tanks. However their shy and cryptic nature is best suited for smaller set ups where you can observe them more easily.
Like all Plectranthias, do not let their tiny nature fool you. Although P. inermis is one of the smallest in the genus, they are not delicate like some species of nano gobies. Frozen pieces of mysis shrimp will be devoured with gusto. Bold, yet not aggressive. If you like something that keeps to your rock work and corals, and shows up every now and then, then P. inermis is the perfect fish for you.
I’ve always liked secretive reef fish that adds another dimension to live rock and coral structures. An occasional glimpse of that cryptic Priolepis goby for example, or the emergence of a careful Pseudochromis, the cautious Plectranthias that lives in that crevice. The next time you see one at your LFS, consider getting one, especially if you have a smallish tank. You’ll be hooked and who knows, the next person shelling out dubloons for an amazing Plectranthias sagamiensis could be you.