A Panamic Barnacle Blenny in its burrow pictured at Captain’s Rock dive site in the Manuel Antonio State Park, Costa Rica.

Upon surfacing after a dive, the first words that escape a diver’s lips are usually about the best marine life they saw during the dive. Some divers are ecstatic about sharks, some love turtles, while others mention interesting looking starfish. Regardless of what creature it is that gets your heart racing, there’s no denying that we all beam with joy after encountering that beloved marine creature.

When it comes to macro marine life, nudibranchs pretty much steal the show. If you’re a diver with a fondness for the little critters, odds are you know the names of a few different kinds of nudibranchs or even remember the first time you saw one. But there’s another little creature in the running for cutest underwater animal: the blenny

There’s more to me than just my cute face


Hover over a rock long enough and if you’re lucky, you’ll see a blenny staring up at you. Well, up at you with one eye while the other rotates in another direction, most likely. Measuring approximately 2 inches, blennies are small fish that belong to the suborders Blennioidei (blennies) and Notothenioidei (Antarctic blennies). They have long, tapered bodies, a continuous dorsal fin and live in burrows on the ocean floor, in reefs, in kelp or mollusc shells. But there’s more to them than just that:

  1. Going rogue
    Don’t let their adorable appearance fool you, blennies aren’t always adorable. There are about 400 different species of blennies and, while some of them have a calm temperament, not all of them do. Fangblennies from the Indo-Pacific sport a set of recurved canine teeth and aren’t afraid to use them on divers or swimmers who get too close for comfort. They even fight each other in territorial battles.
  2. Small but sneaky
    For fish that measure about two inches, they use clever tactics to outwit their prey. The blue-striped fang blenny and combtooth blenny mimic cleaner wrasse – attracting other fish in search of a good cleaning. The blennies take advantage of this opportunity and will often remove chunks of skin off their prey in these surprise attacks.
  3. Not very confident swimmers
    Blennies are mostly bottom dwellers. They find their burrow and will stay nestled there, waiting for food to come to them. As a result, many blennies lack a swim bladder, causing them to lose their ability to swim.
  4. Good father figures
    Female blennies will deposit their eggs in clumps on the surfaces inside their burrows. While some females do it, it is mostly the males who guard the eggs until they hatch. Even during the hatching, male blennies will be present and energetically fan the eggs. After this, however, the hatchlings are left to fend for themselves.
  5. Unique facial markings
    If you’ve ever seen a blenny up close, you’ll have noticed that they appear to have eyebrows and they often have their mouths open – which creates a curiously anxious facial expression. While these characteristics aren’t unique to respective blennies, studies have found that the markings on their faces are unique and can be used to identify individual blennies.

So the next time you’re searching for macro marine life, see if you can spot a blenny poking its head in and out of its crevice. Many scuba divers say that all it takes is one sighting – after which it becomes second nature to spot these adorable and diverse little fish.