Worldwide, there are approximately 900 species of blennies in six families. The number changes every year. Scientists and naturalists are finding new fish, and DNA studies are revealing new relationships… so the number is changing as new discoveries and revisions are made.
Blennies come in many shapes and sizes so why are they all blennies? What constitutes a blenny are certain internal characteristics that set them apart from other fishes. These are not things that we, as fish watchers, will see. I asked Dr. Bill Smith-Vaniz, an ichthyologist who has formally described many blennies, to sum up what constitutes a blenny. I’m paraphrasing..”They all have a bean shaped pelvis, unlike other fishes that have flat to concave pelvic bones, their anal fins differ from other fishes in the number of spines and types of fin rays, and the first vertebra is different in blennies.” Again, these are not characteristics fish watchers will see.
Blennies are found worldwide in tropical and temperate waters in many habitats. Most lack a swim bladder, which is why we see them perched on the bottom, skittering around. And unlike some reef fishes, like parrotfishes and wrasses, they are not hermaphroditic - they don’t change sex.
A Very Unusual Blenny
Xiphasia setifer, a.k.a., Eel Blenny, Hairtail Blenny or Snake Eel Blenny, this Indo-Pacific species is one of my favorites because it is so unusual. We encounter them occasionally, because we frequent their turf - mucky or sandy bottoms. It is difficult to get good footage because they are either entrenched in their burrows or swimming back really fast to escape from us!
Blenny Feeding in North Sulawesi
I shot this video years ago in North Sulawesi, Indonesia, when I found one out feeding.
When is a Blenny Not a Blenny?
A Scooter Blenny is Not a Blenny
When it is a Scooter Blenny. Although blennydom should be happy to count such a lovely little fish among its members, the Scooter Blenny is not a blenny – it is a dragonet.
A Convict Blenny is Not a Blenny
Even we are guilty of perpetuating this name. Pholidichthys leucotaenia is not a blenny (nor a goby); it is in fact in its own family. The correct common name is Convict Fish. I am obsessed with this fish and will write a complete post about them later. There are lots of photos of the adult on the internet – taken mostly in aquariums. I understand from my aquarist friends that they are much more colorful and not as cryptic as the adults in the wild. Here are photos of the juveniles and the very much larger (and dark) adult:
The Pacific Red Lionfish has received a lot of press for its unwelcome presence in the Western Atlantic but blennies have also invaded and become established. The Muzzled Blenny, Omobranchus punctatus, a native of the Indo-Pacific, has been reported from the Atlantic, Caribbean, eastern Africa and Mediterranean. The first record of the blenny in the Caribbean was in 1931 when it was described as a new species, based on a specimen from Trinidad. That was corrected in 1975 when the 1931 specimen was found to be O. punctatus. Known also from Panama, Colombia, Trinidad, Tobago and Brazil, the blenny is believed to have been introduced by ship, possibly in ballast water or barnacles.