There are over 900 species of blenny that are known, with dozens of species common to the aquarium hobby. They vary in color significantly, with one genus containing blennies with venomous fangs! Once they have a happy cave to call their own, blennies are a peaceful addition to many well-secured community saltwater tanks.
Common Name: Blenny
Scientific Name: Meiacanthus spp.
Adult Size: 3 to 5 inches
Life Expectancy: 2 to 6 years
|Tank Level||Mid- to bottom dweller|
|Minimum Tank Size||30 gallons|
|pH||8.1 to 8.4|
|Hardness||8 to 12 dgH|
|Temperature||74 to 82 F (23 to 28 C)|
Origin and Distribution
There are many different genera and species of blennies. "True" blennies are members of the order Blenniiformes. They are found in many areas of the world and in recent years some species have now been allowed to be bred in captivity.
The genus Meiacanthus is made up of venomous blenny species. They have venomous fangs that they use for self-defense. If you own these species, please be aware of your blennies when cleaning the tank or moving decor. Do not let children put their hands in the tank and never hand feed them.
Colors and Markings
Blenny colorations vary widely. Most blennies have elongated bodies and many use their pectoral fins as props to rest on the bottom of your tank and decor.
Depending on your species of blenny, they may be one color throughout, such as the Canary Blenny, or have a mottled color to blend into their background, such as the Sailfin Blenny. Unlike other common reef species, blennies may be dark or bright in their color pattern.
Blennies are semi-aggressive fish and do well with many other semi-aggressive community reef species. They are coral safe but will often hunt small plankton living on the surface of algae and live rock.
Blennies like having a territory to call their own, so they do not do well with small, similarly minded species, such as dottybacks and damselfish. They will use those venomous fangs on their tankmates if they are scared or stressed. Once they have a happy home, they are usually very easy-going community tankmates.
Blenny Habitat and Care
For happy blennies, it is critical to provide them with lots of tiny nooks and crannies. Since they are small, they will not compete for larger caves with large, semi-aggressive fish. You may notice your blenny digging their own cave under rocks and live rock through their gravel or sand.
As with all saltwater systems, proper water quality is crucial for fish health. Keep up with a regular maintenance schedule, keeping in mind that your blennies may be hiding in your cleaning area. Especially with venomous blennies, you need to know where your fish are hiding!
Blennies have been known to jump out of their tanks, so a tight-fitting lid is vital. Do not dismiss their small size thinking they will not leap from their resting spots high up on decor during maintenance or feeding.
Blenny Diet and Feeding
Thankfully, blennies are not known for being picky eaters. They do well with many saltwater community diets. Some specific species of blenny may fall more towards the herbivorous or carnivorous end of the fish spectrum, but most are omnivores.
Venomous blennies forage more in the middle of the water column compared to other blenny species that focus on bottom-feeding. For most saltwater community tanks, broadcast feeding across a wide area of the tank is best to make sure that everyone gets enough to eat without too much competition.
Some species of blenny, such as the Sailfin Blenny, are sexually dimorphic by color, with males being darker than females. But for many species, there are no overt external cues. Sometimes, female blennies are larger than males, but this is not a uniform rule.
Breeding the Blenny
Since it is hard to determine male vs. female blennies, it can be very difficult to start breeding programmes. They can form harems, with one male reproducing with multiple females, so it is recommended to add several individuals to the breeding tank, giving them many caves and crevices, and let them form their own groups.
One male blenny may court one or multiple females. Once the females lay their eggs, the male may tend them in a common nest. Larvae hatch within seven to ten days and require supplementation while remaining in the breeding tank.
More Pet Fish Species and Further Research
If you like blennies, here are some other, unique saltwater species: