Pholidichthys Leucotaenia Care Guide (Convict Blenny)

Convict Blenny - Pholidichthys leucotaenia 3

Last updated on July 27th, 2022 at 11:55 am

If you’re looking to add an interesting species of fish to your saltwater aquarium, the Pholidichthys Leucotaenia may be exactly what you’re looking for. These fish are colorful and extremely active; they love to swim around the tank and play with their owners! With proper care, they can live up to 7 years and produce hundreds of eggs every breeding season!

Pholidichthys leucotaenia, also known as the convict blenny, are very popular saltwater fish. They are popular because they are relatively easy to take care of and they add some interesting color to any aquarium. However, there are some issues that need to be addressed when taking care of these fish to ensure that they live as long as possible and stay happy and healthy in their home.

Convict blennies make excellent aquarium fish if you know how to care for them properly. They are also known as Pholidichthys leucotaenia in the aquarium trade, or commonly as convict goby/engineer goby. These small fish are popular among aquarists because of their bright colors and uniquely shaped bodies, but they can be challenging to keep because of their specific diet and needs for living in groups.

This guide will teach you how to keep these fish healthy and happy in your saltwater aquarium.

Origin and description

Convict Blenny - Pholidichthys leucotaenia

Pholidichthys leucotaenia is a small species of fish that originates from parts of the Indo-Pacific oceans. The specific name leucotaenia is derived from two Greek words: leukos meaning white and taeno meaning ornamented or patched. When translated, it becomes white-patched.

This refers to their dark brown body with white lines on each side and several spots in between that give them a sort of zebra-like appearance. They also have an average size range between 10 – 15 inches in length, but can grow up to 18 inches when given proper care and habitat conditions.

They live in an array of warm environments including both freshwater rivers and streams as well as brackish waters along coastlines with seagrasses. When set up correctly, they make one of the best companions you could ask for; if your tank is not right for them, however, they can become rather aggressive toward other fish.

Generally speaking, though they make excellent additions to most tanks, and here we’ll go over everything you need to know about convict blennies so you can keep yours healthy and happy!

Rhinecanthus verrucosus (Blackbelly Triggerfish)

Species profile

Convict Blenny - Pholidichthys leucotaenia

Pholidichthys leucotaenia is a popular saltwater aquarium fish commonly referred to as convict blennies or just blennies from the Pholidichthyidae family. The origin of their common name stems from their appearance and behavior, which are both reminiscent of criminals. They have blue bodies and white-striped tails that help them blend in with corals and other sea creatures so they can hunt for food without being noticed.

Pholidichthys leucotaenia is a species of temperate marine fish, it inhabits coral reefs at depths between 1 and 20 m, and is native to tropical, subtropical, and temperate waters of Australia.

Although Pholidichthys leucotaenia has been referred to by a number of common names in scientific literature, these were not always synonymous, as each name has been used for more than one species and some of them are still considered ambiguous.

Common names

The most commonly accepted English name is convict blenny, but it has also been called chain blenny, convict-banded blenny, engineer goby, engineer blenny, or red-and-white blenny.

As part of its synonyms, Pholidichthys leucotaenia is also called Brotulophis argentistriatus.


The convict blenny requires a marine aquarium setup with a lot of rocks, driftwood, and coral for it to hide in. These are relatively hardy fish but do require an experienced saltwater hobbyist to take care of them properly. If you don’t already have experience in keeping saltwater fish, consider starting with easier marine pets like clownfish or gobies before introducing something like a convict blenny into your tank.

Additionally, while they aren’t necessarily jumpers like guppies, they can still fall out of their tanks if there isn’t something high enough on their side to hold onto. Glass lids on tanks that reach above two inches give these fishes more freedom and help them feel more secure than having no lid at all! By providing enough caves and hiding places around their home aquariums, you give your pet blennies more options when it comes time to dive out of sight.

Pholidichthys leucotaenia size

Convict blennies are usually small, growing to a maximum length of 24 inches (60 cm).

Pholidichthys leucotaenia tank size

This fish will do best in a tank with at least 20 gallons of water that are moderately planted with live rock. The blenny will appreciate plenty of nooks and crannies to explore, so make sure to choose an aquarium that has ample hiding spots. To keep your blenny happy and healthy, try placing it into a reef-safe tank.

Flame Angelfish (Centropyge loricula)

Pholidichthys leucotaenia tank set up

For a great starter aquarium for Pholidichthys leucotaenia, you will need a tank with lots of places to hide and structures to climb. Make sure that your filter isn’t too strong because these fish are known jumpers. You should also have rocks, gravel, and plants in your tank if possible.

The most important thing is having plenty of algae or macroalgae growing on them so they can feed off of it. I would recommend live rock over artificial rock for Pholidichthys leucotaenia. Also, make sure there are no sharp edges to hurt them. Do not put aggressive fish in their environment as they could be picked on by other fish. Live plants can be used but are not necessary.

In fact, Pholidichthys leucotaenia care may prefer bare bottom tanks so take into consideration its preferences before using live or fake plants and driftwood. It doesn’t matter what type of lighting system you use as long as your temperature stays stable at around 72 degrees Fahrenheit at nighttime temperatures and 78 during daytime hours.

Consistent water changes must be done every two weeks even though water quality is good. Be careful when cleaning out substrate as you do not want to disturb hiding spots that these fish inhabit during resting periods.

Pholidichthys leucotaenia tank mates

Keep your Pholidichthys leucotaenia in a tank with other peaceful fish. Because they do tend to be territorial, keep only one per tank. When you add it to a new aquarium, don’t add any other fish for at least two weeks.

If you do add another blenny or other species, watch carefully for signs of aggression and remove your new addition if it is being bullied by your convict blenny. You may also want to provide plenty of hiding places where your Pholidichthys can escape its meaner tank mates.

Some good tank mates are clownfish, anthias, dottybacks, hawkfish, shrimps, dwarf Angelfish, Wrasse, damsels, and filefish.

Pholidichthys leucotaenia breeding

Convict Blenny - Pholidichthys leucotaenia

Pholidichthys leucotaenia are egg-scatterers that can be bred in captivity. The male tends to take care of eggs, but with a nest size of up to 2000 eggs, it’s still important for him to have plenty of food so he does not become weak and die. The female is far less picky about what she eats and will accept almost any meaty food.

Synchiropus Splendidus (Mandarin Dragonet)

Both fish can be very defensive if their territory is invaded. Keeping multiple pairs together may help reduce aggression, but they must be well fed and large enough so they don’t attempt to consume each other. If breeding these fish, you should also keep in mind that many types of blennies may only reproduce once per year. You might want to consider giving them a resting period between spawns to increase your chances of success.

Are Pholidichthys leucotaenia aggressive or peaceful?

Generally speaking, Pholidichthys leucotaenia (most commonly known as convict blennies or striped blennies), are peaceful and can be kept in a community aquarium. However, they are a predatory fish species and will often take advantage of any injured or sick fish in their tank. They also have been known to nip at more delicate corals in tanks with soft coral growths.

Pholidichthys leucotaenia care

Convict Blenny - Pholidichthys leucotaenia

The convict blenny is a great beginner fish. They are reef safe and very hardy. In addition, they can tolerate low water quality and require minimal maintenance in comparison to other saltwater fish species. However, they do have specific needs that must be met in order to maintain their hardiness and may not be appropriate for all aquarists.

The most important factor in determining whether or not your aquarium environment is suitable for a convict blenny is that it provides ample amounts of living space within its provided tank space.

Pholidichthys leucotaenia diet

Like all in their genus, Pholidichthys leucotaenia is an omnivore. While they are willing to eat a wide variety of foods and will accept flake food, they should be provided with as much live or frozen fare as possible. Small crustaceans such as shrimp and amphipods make great additions to their diet and can also be fed on a more regular basis than live brine shrimp.

Water parameters

Convict Blenny - Pholidichthys leucotaenia

A high pH of 8.0 – 8.4, a water hardness of 5 – 19 dGH, and an ideal temperature range between 74 – 82°F (23 – 28°C) will provide optimal conditions for Pholidichthys leucotaenia.

In addition to these basic parameters, you should also ensure that your blenny is kept in clean water.

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It is recommended that you perform 25% weekly water changes on your tank to avoid harmful ammonia and nitrite levels from developing within your tank. Maintaining good water quality is essential for maintaining good health in marine fish like Pholidichthys leucotaenia.

However, if your tap water contains chloramines (many municipal tap water do), it must be either removed or neutralized before being added to your aquarium. Chloramines cannot be removed by ordinary chemical dechlorination; aquarists must use one of several commercially available products designed to neutralize chloramines.

Pholidichthys leucotaenia lifespan

Approximately, they can live for 5 to 7 years in captivity.

Parasites and diseases

These tiny creatures are a big concern when keeping fish, and can be found in varying degrees in aquariums of even experienced aquarists. A number of parasites that infect marine aquariums can affect blennies, including monogeneans (single-celled organisms), digeneans, acanthocephalans, copepods, and isopods.

Other external parasites include flatworms and nematodes. Within most species of pholidichthyids, there have been documented cases of other viral infections such as ichthyophthirius multifiliis, which causes ick or white spot disease. Lastly, there are diseases caused by bacteria such as vibriosis and columnaris; these types of infections cause red or white patches on your blenny’s skin respectively.


The possible predators of Convict Blennies are just as varied as their preferred habitat. In fact, most fish make a meal out of them at some point or another. This can be a good thing since it’s usually an indication that they have plenty of food in their environment.

Grouper and large Triggerfish both have been known to enjoy these fishes on more than one occasion, while predatory snails such as Triton Snails will also chow down on them if given an opportunity.

Other threats to this fish are sharks and striped eel catfish (Plotosus Lineatus)

Do they make good pets?

Yes. They are hardy, inexpensive, and a great tank addition to new saltwater hobbyists.