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Bicolor Blenny Fish Care Guide

The Bicolor Blenny fish is a must for any tank because it brings colour to your tank, with its dual-tone colouring, brown front half of the body and a yellow-orange tail half.

What Does The Bicolor Blenny Fish Look Like?

The Bicolor Blenny fish is a dual coloured fish without flashy colors. The coloring is bluish/purplish/brownish front half and an orangish/yellowish posterior.

The color is not a clear-cut brown or yellow but leans towards a gradient of colour like a palette on a color card chart.

It has a slender elongated body, one long dorsal fin, which makes it look like a sperm whale's head, bulbous eyes and has two antennae protruding from between the eyes.

Is often confused with the goby family due to its similar looks. Males are generally larger than females and undergo several changes in color during the breeding phase.

What Is Their Scientific Name?

Bicolor Blenny fish scientific name is Ecsenius bicolor. It belongs to the Animalia kingdom and phylum Chordata. It is also known as the "flame tail Blenny.

This fish is in the class of Actinopterygii which are basically ray-finned fishes. It belongs to the order Perciformes which are also known as perch-like fish.

This order contains forty-one percent of all types of fishes and a majority of bony fish. Most fish found in the aquatic environment belong to this order. It belongs in the family of Blenniidae, also known as comb-tooth blennies.

They derive the name comb-tooth from their comb-like teeth on the lining of their jaws. They are found in tropical and subtropical waters. The fishes have a blunt head and large eyes.

Genus Ecsenius is one of the largest genera in family blennies and it has fifty-eight fish and has eighty species. The species name is E. bicolor.

Are They Aggressive?

The Bicolor Blenny is a funny fish. It is not aggressive to other fish but gets very agitated and aggressive towards its own kind, unless it is the opposite sex. Unfortunately, there is no way to distinguish sex by external characteristics.

If it is housed in a huge tank, then these territorial instincts does not show up so often, but with smaller tanks, due to the space limitation, this territorial quirk flares up. They also tend to nip and nibble at coral in the tank.

They are prone to darting back to their holes or behind the rocks when they see a human approaching the tank, even during feeding time.

Although it may sometimes nip at the coral, this Bicolor Blenny hardly causes any damage to the corals or invertebrates. It has to be kept well fed with microalgae to keep it from attacking any of the polyps or corals. It surely helps to keep your aquarium clean.

Are They Beginner Friendly?

It is rather easy to maintain as it does not require very high technical knowledge. All the beginner needs to know is that this fish is a herbivore and sometimes an omnivore.

It lives on algae so sheets of algae can be brought and fed to it in very tiny pieces. If larger pieces are fed, it will just pick them up and spit them out again.

The tank also does not need too much cleaning as the fish does it for you. The most important thing for the beginner to remember is that this fish is a jumper.

Even while feeding, utmost care has to be taken as they will jump at the first opportunity.

How Long Do They Typically Live For?

They normally live up to 10 years in captivity. During spawning the males, who are generally bigger than the females, exhibit colour changes.

As in all fish, Bicolor Blenny is also susceptible to saltwater disease which is normally brought about by stress during transport as well as improper acclimation, or the water quality has deteriorated.

Ich is another disease this fish catches easily, which is again due to stress. Ich is easy to treat if caught in time. The best way to treat ich and any other disease is to move the sick fish to quarantine and treat there, instead of dropping the medicine in the tank which might have an adverse effect on the other fish or invertebrates in the tank.

If you have too many fish in the tank, the nitrite and nitrate levels will rise, you have to change the water immediately.

What Things Do They Eat?

This fish is a bottom of the tank dweller and mostly eats algae. You can supplement its diet with live macro algae, such as Macro Feast, and dry seaweed 1-2 times per week.

Try using a rubber-band to attach the algae to a small rock or PVC pipe and place it in the sand bed. Bicolor blennies are herbivores who thrive on dried and frozen fish food made for marine herbivores.

A good mix of green foods, including various algae-based dried foods and frozen herbivore formulations, should be offered.

They must have live algae or they will die. It is important to provide grazing opportunities. Even tiny patches of algae are good enough for them. Soaking all fish food (even algae) with vitamins will help keep your fish healthier and make them less susceptible to disease.

We recommend soaking food in garlic as well when adding new fish and whenever you notice ich or another disease in the aquarium. Garlic will help repel external parasites and will boost the fish’s immunity.

Fresh frozen mysis shrimp is a great food for them, besides it is higher in natural protein than most other foods.

What Is The Best Size Tank For Them?

A 30-gallon tank is the most preferable tank for them. It must have plenty of live rock hiding places and a tightly sealed top lid as they are very good jumpers.

They are used to jumping from pool to pool. Be warned, If your lid is not shut they will escape! The great thing about them, is they help to clean all algae growth on the sides and bottom of the tank.

What is the the Best Water Temperature and PH Levels?

The water temperature should be a stable 75-80F, not deviating by more than a 2-degree range, specific gravity 1.024 to 1.025, pH 8.1 to 8.4.

Also, there should be Calcium of between 420 and 440ppm. Alkalinity should be between 8 and 9.5 dKH, Nitrates less than10 ppm, Mg 1260 to 1350 and Phosphates less than10 ppm.

There should be no ammonia. If you find the nitrates rate has risen above 10ppm, you have to change the water immediately. Maintaining proper calcium and alkalinity levels will keep the pH stable.

Tank dimensions should be 36 1/4 by 12 5/8 by 16 3/4. and weighs about 43 lbs.

Can You Keep A Bicolor Blenny Fish In A Nano Tank?

First of all, let us see what is a "nano tank". It is typically a tank with approximately 10 gallons of water 20 inches by 10 inches by 12 inches and weighs about 11 lbs.

It is an alternative to the large, heavy tanks that use too much water and take up too much space in the home or office. A Bicolor Blenny is a territorial fish and attempts to defend its territory, so putting it in a Nano tank with other species would mean it would be constantly stressed, but if kept by itself with many hiding places it would thrive.

A Bicolor Blenny gets along a bit better with some other species than another Bicolor Blenny. Providing plenty of live rock with microalgae for it to graze on should keep it pre-occupied.

It is basically not a swimmer but a jumper, so a smaller tank will not make too much of difference if sufficient rocks are provided in the Nano tank. It will be a very happy fish if the rocks are live and have holes and algae on them.

The most important factor is that the tank must be covered with a lid to prevent carpet surfing.

What Is The Best Tank Setup?

The bicolor blenny has unique personality that distinguishes it from other fishes. They generally live their lives amid rocks and crevices deep down inside water.

So when you are setting up their tank, it is advisable to get rock particles scattered all over the bottom of the tank for hiding and perching. Naturally, they enjoy they enjoy being far from the surface, so they can eat the algae.

So, you need to fill your tank with enough water so they can be comfortable staying at the bottom of the tank. Don’t put more than one blenny in a tank because they can feed on themselves.

The blennies can live peacefully in tanks but they need lots of space to move around freely without hitting against the tank. Therefore, endeavor to create more space (minimum of 30 gallon) for each blenny.

Water management is another great aspect to consider when taking care of blennies. The water quality should be kept clean always by changing about 10 to 15 percent of it every month.

What Are The Best Tankmates For The Bicolor Blenny Fish?

Blenny can thrive in an environment that has other species of fish. However, caution must be taken when selecting the kind of mates to introduce.

For example, you wouldn’t want to put fish that are bigger than blennies in the same tank because the blennies are likely to be converted to menu in hard times. 

I have seen some cases where people put them with other species, but the size of the tank must be large enough for both species to live separately. They like to have a space to themelf and you need to respect them for that.

If you must find a tankmate for blennies, then I have seen Malacanthid in the same thank with a blenny, and would recommend it. But if you know your tank is not large enough, forget it.

Can They Share Their Tank With Their Own Kind?

Keeping blennies together in the same tank is never a good idea. Do not fall for the idea of keeping so many of them in the same tank, regardless of how attractive the idea is.

So if you must, for any reason, put two blennies in the same tank, you must ensure that the tank is big enough to contain them. Feeding must be done at the appropriate time to avoid cannibalism.

Where Is Their Native Location?

They are natively found in Phoenix Island, Maldives, Samoa, Ryukyu Islands, southwards to the Great Barrier-Reef, and Micronesia. Blennies are decreasing in population and this has led to some measures put in place to prevent their extinction.

Among the countries where you can find blennies include the following;

  • American Samoa
  • Australia
  • Indonesia
  • Cocos Island
  • Guam​
  • Fiji
  • India
  • Kiribati
  • Japan​
  • Marshall Island
  • Maldives​
  • Malaysia​
  • Marshall Island​
  • Philippines​
  • Papua
  • Samoa​
  • Solomon Island​
  • Papua New Guinea​
  • Nauru
  • Myanmar
  • Nauru​
  • New Caledonia​
  • Taiwan​
  • New Caledonia​
  • Sri Lanka​
  • Thailand​
  • Tokelau​
  • Tonga​
  • Hawaiian Island in the United States​
  • The Northern Mariana-Island​
  • Tuvalu, Wallis​
  • Futuna​
  • Wallis​
  • Vanuatu.

If you wish to fish for bicolor blennies, there are some native fishing areas that are FAO marine fishing approved. They include western Indian Ocean, eastern Indian Ocean, eastern central of the pacific, and northwest of the pacific.

What Is The Ideal Water Temperature?

Most people are ignorant of the fact that there is an ideal temperature required for blennies to thrive. Ideally, a temperature of 75 to 85oF or 24 to 29oC should be maintained if possible to make the fish feel at home.

It is okay if you can’t get the exact ideal temperature but water temperature in your tank should be very close to the ideal readings if you must keep blennies as pets.

When it comes to keeping fish as pet, one major factor to give full attention is water management. Blennies can be kept in reef aquarium, but if the temperature of the water in the tank is not favorable to the fish, it could lead to stress and subsequently diseases.

The water temperature is one aspect you should consider because a lot of people have lost their precious pet due to poor water temperature.

Is It Easy To Breed Them?

Breeding of bicolor blennies is quite possible but challenging if you must know. When they are in their natural or native habitat, it is quite easy for the females to lay eggs in crevices, and guard them until they are ready to hatch.

Spawning in a home aquarium is a different ball game and will require some effort from you if you must succeed.

For breeding to take place, both the male and female fish must come together. This means that they must be kept in the same tank.

At first, you will notice some kind of serious fight between them, then after sometime they will go to a comfortable hiding place to rest. Fertilization takes place after some days and the eggs are hatched.

Now, after hatching it is the stage that you have to be extra-careful in order not to lose them. According to many accounts online, the hatching stage is easy but what follows thereafter is quite the challenge.

This is often due to wrong feeding practices and lack of water maintenance. You need to change about 10% of the water daily and feed them moderately with rotifer.

So like I said, getting the male and female to come together for fertilization, laying of eggs and hatching is possible and requires less stress. However, the main issue is breeding them from fries as well as fingerlings, juveniles and then to adult.

How Effective Are Bicolor Blenny For Algae Control?

Algae is a living organism that thrives in an environment that has enough sunlight and nutrients. If your tank is placed close to a light source, there is high chance of heavy algae growth.

Also, a salt water tank must be kept clean and well filtered to prevent the buildup of phosphate and other nutrients that encourage algae growth.

However, if your tank is already infested by algae, it could be quite challenging to get rid of the algae completely. One of the most effective control measures to use is bicolor blennies.

This fish species can help you control algae to a degree. This doesn’t mean that because bicolor blennies can fight algae, then you should be ignorant of the cause of algae growth.

So instead of allowing your tank to become infested by algae, you can move it away from sunlight if it is situated in a position that receives too much light.

You can also control the buildup of nutrients in the water so that you don’t provide a breeding ground for algae.

Is There A Difference Between The Male And Female?

When Bicolor Blenny are of the same age, there are some distinctions to note such as male Bicolor Blenny fish are a bit bigger in size compared to the female fish. Also, the male fish is slimmer and more vibrantly colored.

Females have less orange and no extended fin rays while the male has a dip orange color and an extended tail fin. The dorsal and anal fins of the male are more pointed as well as larger and more flowing than female.

Female lay eggs on crevices or at the bottom of the aquarium where there is less disturbance. The eggs will be coated with an adhesive like liquid so that it is held firmly in place.

They highly protect their eggs from predators. The female has a thick genital papilla to enable them to lay eggs. On the other hand, males have a thinner genital papilla. Both males and females, upon hatching from eggs, do not change their sex a characteristic observed in other fish.

During breeding, males may develop blue color as a way of succession. Both male and female develop tail filaments when mature. The male bicolor blenny fish has seminal vesicles instead of the testicular glands.

There is an egg-shaped marking on the anal fin known as the egg spot in males. The females have less orange and no extended fin rays while the male has a dip orange color and an extended tail fin.

Breeding spawning occurs depending on the male body size. Males have pronounced thicker lips and no distinct belly. They also have tubercles on their operculum as well as long fins in general and pointed pectoral fins in particular.

Are They Expensive?

The price is around $16 - $23 this is a decent value considering its wide unique options.

Bicolor Blennies are not expensive as compared to other fish. This is because of several reasons that influence the price such as; the length of the fish, species group, the type of the market, the final consumer of the fish, the weight and the visual judgment of the fish and the form of preservation. Overall, the size and appearance are the major points of consideration.

The feeding costs for the Bicolor Blenny starts around USD 5-20, while for other veterinary and medication needs comes around $50. It's one of the most colorful fish of the Blenniidae family, which makes people desire to have them as pets.

Their ease of handling, less-demanding natural needs and relatively small in shape encourages more people to buy them.

Are These Fish Jumpers?

Yes, they are jumpers. However, there are several reasons that can cause your fish to jump out of the aquarium. Improper cycling of your aquarium can cause Blennies to jump out.

Also, high concentrations of ammonia or improper pH levels can cause them to jump out.

A point you should note is that fish breathe oxygen. Therefore, when the water is dirty there is less oxygen in the fish tank for the fish to breathe. This can cause the Bicolor Blenny to jump in search of oxygen.

Also, a tank without decorations or places to hide can cause the fish to feel bored or overly exposed and want to jump. If you keep the Blenny with a predator fish, they will jump in order to escape or relieve them from the danger.

When Blennies are hungry, they will tend to leap out of the water in search for food such as vegetable matter.

There are several ways to prevent the fish from jumping out of the aquarium such as; putting a lid on your aquarium and choosing compatible tank makes.

You could also consider maintaining good stable water-parameters, limiting excessive noise and providing sufficient hiding places.


The Bicolor Blenny is a great fish to start a new hobby with. Beginners would not have any problem maintaining this Bicolor Blenny either in a reef tank or a Nano tank. It is easy to maintain and you can spend hours watching its antics.

Although it is a timid, peaceful fish it does get territorial when paired with one of its own kind.

The beginner should start with a single Bicolor Blenny and then decide for any more additions. It is not expensive too, at approx $20 a piece. The Bicolor Blenny is the top recommended fish for a home aquarium.


Hey, thanks for passing by, welcome to the blog for Pet Fish fans. This is me, Wayne, and my son Theo. I started this journey after we bought him hist first Fish Tank of fish. Follow my site for my research and info on Pet Fish.