Bicolor Blenny: Guide to Care, Breeding, Diet & Behavior

Bicolor Blenny is a fish that is native to Sri Lanka, Indonesia, and Fiji, and it is a nice algae-eating fish that may add a new spice of color to your fish tank. The front half of the fish is blue or brown in color and this color fades into yellowish-orange as it reaches the middle portion of the fish. Though Bicolor Blenny is mainly an algae-eater, it also eats a wide range of meaty foods.

Bicolor Blenny Fish Care – Size, Life Span, Tank Mates, Behaviour, Food

Bicolor Blenny

Being the owner of a Bicolor Blenny, you should know that this fish should be well-fed if you wish to avoid aggression within the tank mates, even with the corals. Although it is deemed to be reef-safe, this is a species that demands too much space and live rock to perch on, hide and graze on. If they are not given enough space, they instantly face issues with their tank mates even including corals.

Once their nutritional and environmental needs are met, the Bicolor Blenny is certainly one of the best additions that can check and control the growth of algae. If you want to know more about Bicolor Blenny, here are several other details to take into account.

Quick Facts of Bicolor Blenny

  • Scientific Name: Ecsenius bicolor
  • Common names: Bicolor Blenny
  • Size: Maximum of 4 inches
  • Level of care: Easy
  • Lifespan: 2-4 years
  • Temperament: Peaceful apart from other blennies
  • Habitat: Sri Lanka, Fiji, Indonesia
  • Diet: Herbivore
  • Minimum size of fish tank: 30 Gallons
  • Reef-safe: Yes
  • Gender characteristics: Males are larger in size than females

What is the lifespan of Bicolor Blenny?

The predicted lifespan for a Bicolor Blenny usually is between 2 and 4 years but they can live for a year or two more provided it is taken proper care of.

The appearance of Bicolor Blennies

The Bicolor Blenny is blessed with two different colors and hence it gets its name ‘bicolor’. The front portion of the fish is a blend of brown and purple and the back portion is a gradient color between orange and yellow. It has a long body that is slender and smooth and has one dorsal fin, protruding eyes, and two antennas that arise from the eyes. As compared with other tank fishes, the male is slightly bigger than the female.

The behavior of Bicolor Blenny

The Bicolored Blenny is usually reserved and peaceful, spending the maximum amount of time at the bottom portion of the fish tank. They have a habit of picking or disturbing smaller gobies, blennies, and dartfish. If you have reef aquariums, you might be advised to utilize fleshy corals as these fishes are usually underfed.

You will most likely spot it by choosing a fleshy polyp or clams or mantles which usually happens in smaller set-ups of fish tanks. These fishes don’t love swimming too much, they instead hop from one rock to another, choosing small pieces as they move.

Bicolor blennies prefer the habit of carpet surging and this can only be done when you require investing in maintaining a great top for the fish tank. Make sure the tank is always locked. These fishes can be easily bullied by other fishes and hence it is wiser to think twice before choosing their tank mates.


The male, as already mentioned before, is usually larger than the female and it also undergoes various changes, usually becoming blue during breeding. The male fish is slimmer, slenderer, and brighter than the female. Females, on the other hand, don’t have fin rays, that are present in males. The intensity of the orange color also differs between the two as the female is less orange in color.

One more distinction between the male and the female is in its anal and dorsal fins. The dorsal and anal fins are bigger and more noticeable in males than females. As the female blennies will lay eggs, they have a thick papilla near their genitals. The eggs are laid right at the bottom of the tank and this is one of the main reasons behind keeping the tank full every time.

Diet of Bicolor Blennies

Bicolor Blennies are usually herbivores that feed on a wide range of foods. They usually stay in the lower part of the tank and hence their main food is algae. Make sure you keep micro-algae ready if you have Bicolor Blennies in your fish tank.

How are you supposed to feed the fish? Well, since fishes are too susceptible to stress, this means that you shouldn’t disturb the fish’s peace of mind while feeding it. Use a pipe or a rubber band to lower the algae towards the lower part of the aquarium.

One of the most significant parts of these fish diets is a live algae meal and if these fishes continuously live without it, they can lead to death. Hence, you should feed your fishy friend a combination of algae-based dry foods and green foods along with frozen herbivore meals. Just as humans, fishes also need vitamins to boost their immunity to have good skin. You can soak these fish in vitamins for immunity development.

How to take care of a Bicolor blenny?

As long as taking care of Bicolor Blennies are concerned, you have to provide them with a natural environment so that they feel they are in the wild. Since they feel that most of their lives are spent around rocks at the lower level of water, you should have enough rock particles for them to hide.

Bicolor Blennies are sensitive to health conditions or environments and hence it is vital for the water to be replaced every few days and it also has to be clean. The ideal water temperature should be ranging between 23-27 degree Celsius and the pH level should be between 8.1 and 8.4 which means more alkaline.

The calcium content of water should be around 400 ppm, phosphate and nitrate levels below 10 ppm and the content of magnesium should be 1300 ppm to ensure a perfect environment for the Bicolor Blenny.

Therefore, now that you know the details of the Bicolor Blenny, what are you waiting for? Help yourself by following them and keeping them in mind after bringing them into your home.

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