News / Species Spotlight / Japanese Kelpfish (Pseudoblennius marmoratus) (08/01/18)

Japanese Kelpfish (Pseudoblennius marmoratus)

Species Spotlight - Japanese Kelpfish (Pseudoblennius marmoratus)
When is a blenny not a blenny when its a kelpfish or, perhaps a bit more accurately, a sculpin. Pseudoblennius, despite its blenny-like nomenclature, actually belongs to the family Cottidae. This group isnt going to be familiar to the average marine aquarist, as its 275 or so members are more or less restricted to temperate waters, far from the tropical reefs from which most of our fishes originate.

The Japanese Kelpfish (P. marmoratus) is one of few examples from the sculpin family that youre ever likely to see available. Dont let the name fool you, this is no close relative of the true Kelpfishes. Those belong to an entirely different family, Chironemidae, which occurs only in the subtropical and temperate waters of Southern Australia. Confusingly enough, the only species available to aquarists from both of these groups is named marmoratus, but that is where the similarities end.

Pseudoblennius marmoratus resides in algal reefs along Japans southern coastline and into South Korea. A total of six species make up this genus, all of which occur in this same general area, and they are very tricky to tell apart. They all share a similar marmorated color patterning, which refers to the marbled appearance formed from the many irregular markings that adorn these fishes. And, making things even trickier, the colors of the Japanese Kelpfish, depend heavily on where and when they were collected, as they can adapt their colors to match the local algal community.

Fully grown specimens will reach only around 4 inches in length, making them highly suitable for smaller aquariums. However, this is not a species to recommend for the typical tropical fish tank, as cooler water temperatures are needed. And dont let the blenny name fool you, these are highly predatory fishes, more than capable of taking down smaller fishes. Specimens are not terribly picky, though, and can be fed on an assortment of frozen and dry foods. Unless housed in a suitably large system, only a single specimen should be kept.