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A Fascinating Look into the World of the Blenny Fish

The fish known as the Blenny is a fascinating creature that’s not as widely-discussed as many other varieties of fish. In fact, the Blenny is a relatively new entry onto the fish-keeping scene, despite being discovered in 1973. With that said, they can be a fantastic addition to any home aquarium. Taking the time and effort to learn more about them can help ensure that you set up an environment that provides all that a Blenny needs.

A Deeper Look into their Natural History

Blennies are found in shallow-water areas near coral reefs. They are members of the Blenniidae family and are also referred to as Combtooth Blennies. They come in two varieties, with the first being the Marine, and the second is the Freshwater Blenny. Naturally, the Marine breed inhabit saltwater, while those of the Freshwater variety take up residence in freshwater tanks.


Blennies can be identified by their larger eyes and slimmer bodies, their sharp-toothed mouths, and their frilly fins. Most varieties of Marine Blennies can grow to a maximum length of around 9-inches, with the average being just a bit smaller. Freshwater Blennies, on the other hand, tend to stay quite a bit smaller, with the majority falling in the range of 1-4 inches.

The coloring of Blennies is quite varied, though most tend to be shades of yellow, brown, and green. Those colors often feature a combination of stripes, spots, and other patterns, making each one quite unique.

Diet and Feeding Habits

The diet of a Blenny is largely comprised of small insects, copepods, and other small invertebrates. They are scavengers, in the sense that they’ll sift through the substrate in search of food.

In captivity, a Blenny should be fed a varied and balanced diet that provides all of the necessary nutrients. Flake food and freeze-dried products can be supplemented with frozen foods such as mysis shrimp, blood worms, and brine shrimp. A meal of small live foods will be enjoyed and should be offered on occasion.


The Blenny is an active creature and will explore their environment quite regularly. They do tend to be a bit on the shy side, however, so it’s important to provide them with plenty of hiding places. It’s also important to keep in mind that they are curious and may occasionally wander far from their tank in search of new experiences, potentially causing harm in the process.

Blenny two

Relationship with Tankmates

As a part of their natural behavior, Blennies may display aggression towards tankmates when they feel threatened. While they are generally peaceful towards larger fish and marine invertebrates, they may become territorial if kept with other species of Blennies or fish of similar size.

Interesting Facts about Blennies

There’s A lot to learn about this unique underwater species:

  • Blennies have vertically oversized eyes, which help them better detect food sources.
  • Most Blenny species are reef safe and won’t cause any significant damage to their environment.
  • Although they’re classified as carnivores, they’ll feed on algae in an aquarium setting.
  • Since many Blenny species are highly territorial, they should only be housed singly.
  • Some Blennies can remain motionless on the rocks while they wait for their prey.

Caring for the Blenny

The care of a Blenny is relatively easy, as long as certain conditions are met. Firstly, a moderate amount of water movement and good filtration are necessary. As for parameters, a temperature of anywhere between 76 and 79 degrees F is ideal, and the pH should be slightly alkaline (7.8 to 8.4). A 30-gallon or bigger tank is needed for a Marine Blenny, while a 10-gallon tank will suffice for freshwater species. As for decorations, plenty of hiding places, rocks and aquatic plants all help to provide a Blenny with the proper environment.


The Blenny is a fascinating fish that’s sure to add some personality to any home aquarium. Not only are they interesting to observe, but they also tend to be quite entertaining as well. With the proper care and the right tankmates, this unique fish can be a great addition to any aquatic setup.

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