The Lawnmower Blenny is a small marine fish species that many aquarists find to be an interesting fish to keep their saltwater aquariums.

If you are trying to support a diverse saltwater ecosystem, this breed of Blenny can help keep algae at a minimum. Also, this will prolong the life of your fish and contribute to an overall healthier habitat.

Not only are Blennies helpful, but they are also entertaining. Whether you are starting a new saltwater aquarium for the first time or you are looking for some fun fish that can help keep your existing tank clean, you’ll find the Lawnmower Blenny to be a popular option.

They are pretty easy to take care of, and they provide plenty of entertainment. The below guide will give you the details you need to take care of a new Lawnmower Blenny fish with success.

Quick Facts:
Common Names	: Lawnmower Blenny, Jeweled Blenny, Algae Blenny, Sailfin Blenny, Jeweled Rock Skipper
Origin	: Indian and Pacific Ocean
Family	: Blenniidae
Scientific Name	: Salarias Fasciatus
Care Level	: Modarate
Temperament	: Aggressive on same kind
Social	: Community fish
Diet	: Herbivore
Size (average)	: Up to 6 inches long
Lifespan	: Up to 4 years
Breeding	: Egg layer
Minimum Tank Size	: 30 gallons
Tank Environment	: Saltwater, Sandy substrate, Rocks, Lots of Marine algae
Temperature	: 72 – 78 °F (22 – 25.5 °C)
Water Hardness	: 8 - 12 dKH
Water pH Level	: 8.0 - 8.5

Overview of Lawnmower Blenny

Lawnmower Blennies are a very interesting species of fish that serve a specific purpose in the ocean: to clean the environment by trimming back algae. As their name might imply, Lawnmower Blennies eat growing algae to keep it from filling up too much of the water.

Since they are often found on reef floors and in rocks, they have been given several other nicknames, including:

• Sailfin Blenny
• Algae Blenny
• Jeweled Rock Skipper
• Jeweled Blenny

Lawnmower Blennies eat several types of algae to keep their habitat free from contaminants. A good way to keep the levels of algae in your tank under control is to invest in a Lawnmower Blenny for your aquarium.

Origin, Distribution, and Availability

In the wild, you’ll find Lawnmower Blennies and many of their cousins in the Indian Ocean. They are mostly found off the coast of eastern Africa, but they have been located in the Great Barrier Reef, the Red Sea, and other parts of the Pacific Ocean as well.

This particular species of Blenny is known as Salarias Fasciatus, which is one of 13 different genus types. Their diversity and hardiness make them solid aquarium companions and good tank mates for many saltwater fish species.

Lawnmower Blennies are bred in captivity all over the world, and it is not difficult to find farms that sell these algae-eating fish. In fact, the Lawnmower Blenny is one of the most popular types of Blenny fish that aquarists want to get their hands on.

This makes them pretty readily available just about anywhere. You can search online or look for a local fish shop that may sell individuals of different sizes.

Lawnmower Blenny Typical Behavior

If you see a Lawnmower Blenny at the bottom of the tank, the fish is not sick – this is where Blennies prefer to live. They are almost always laying amongst the substrate or hiding within decorations that you may have placed around the tank.

They also place themselves amongst rocks and grip onto them, making them difficult to remove if you ever need to do so (although a friendly fish trap will do the trick).

Lawnmower Blennies are very intelligent, and you will often see them observing what is going on outside of the tank. They can pay attention to shapes and sounds, and their large eyes might even follow you as you walk from one side of the tank to the other. They are naturally curious, using their eyes and fins to explore the world around them.

Each Blenny has its own personality. This usually leads to playfulness and fun times in the aquarium, but can infrequently cause aggression. These fish do not usually display violent behaviors, but they can become more temperamental as they age.

You might see them fighting off members of their own species, but they rarely attack others.

Blennies usually sit still on rocks, but you will occasionally see them jumping from rock to rock in search of food. This gives them a bit of charm that makes aquarium owners fall in love with them as soon as they are added to the tank.

Characteristics of Lawnmower Blenny

Most marine aquarists agree that Lawnmower Blennies are cute; not just because of the way they look, but also because of their personality. There are a number of unique features and characteristics that all contribute to this fish’s lovable popularity.

Appearance

Lawnmower Blennies have incredibly large and round eyes. These bulbous orbs rest on top of a blunt-shaped head, and they can scan the environment at almost 360-degrees. Their large field of vision pairs well with the outward-facing mouth.

White stripes come from each of the Blennys’ black pupils, with blue dots surrounding each eye. These are some of the unique features that make the Lawnmower Blenny look colorful and appealing.

They sport a dorsal fin and comb-shaped fins on each side of their body to help them navigate murky waters. The fins help them hop from rock to rock and sweep through the sand in search of algae to eat. Their teeth are hard and pointed, helping them scrape algae off of hard surfaces.

Colors and Special Markings

The colorful white and blue markings around their eyes are the most vibrant parts of the Lawnmower Blenny; most of its body is covered in browns and greys to keep it camouflaged against rocks.

Some Blennies have patterns of brown, cream, and green stripes or bands on their bodies. They are usually not very noticeable, as the fish still needs to rely on its natural-looking colors to blend in.

Lawnmower Blenny Size

A fully-grown healthy Lawnmower Blenny will be between 4-6 inches. With the right care, diet, and tank conditions, you can expect your Blennies to get this big within a year or two.

Make sure that you have enough space in your tank to accommodate a fish that can grow up to 6 inches long. This is usually a little bigger than people expect!

Lifespan: How Long do Algae Blennies Live?

The average lifespan of the Lawnmower Blenny is about 4 years. But again, good tank conditions and a balanced diet could ensure that your fish live for even longer.

Many aquarists have had Lawnmower Blennies in their aquariums that have lived for 5 years or longer.

Aquarium Care and Conditions for Lawnmower Blenny

If you want to have happy and healthy Blennies in your aquarium who can help you stem the tide of growing algae, you need to take care of them properly. It is not hard to care for the Lawnmower Blenny, but you will have to have some knowledge of their health requirements before you purchase these fish.

The most important part of caring for Lawnmower Blenny aside from diet is having the proper tank setup. The right water conditions, plants, rocks, and substrate can help your Blenny thrive in your underwater ecosystem.

Tank Conditions and Care

The Lawnmower Blenny’s habitat must be similar to the natural habitat that they would have in the ocean. In the wild, this fish lives in shallow reefs and lagoons. These places have lots of coral rubble, sponges, stones, and lots of places for algae to grow.

They almost always live among the substrate, so this is one of the top things to consider when setting up your tank for the comfort of your Lawnmower Blenny.

Tank Size

Since Lawnmower Blennies can grow to be up to 6 inches long, they need a significant amount of space in the tank so that they don’t feel cramped. If they don’t have enough room to swim around, they can become aggressive with other fish.

For this reason, it is recommended that you keep at least a 30 gallons saltwater aquarium for your Lawnmower Blenny. If you plan on housing more than one, you should add an extra 30 gallons for each fish.

Tank Setup

Your choice of substrate could make or break the Lawnmower Blenny’s comfort. They need a rocky environment, so make sure to lay down a layer of sand and fine substrate first.

Then, cover it with live rocks and decorations that give these playful fish plenty of places to hide themselves away when they aren’t actively looking for food. Although, keep in mind that a more natural-looking environment is preferred.

Don’t fill the tank with too many rocks and trinkets. Blennies still need space to swim around!

When it comes to lighting, you can use any sort of standard tank lighting and your Blenny will likely be comfortable. But you should stay away from really bright lights as this could make the fish sick.

Suitable Plants

Natural and live plants are a great thing to add to your tank for Lawnmower Blennies, as they can use the leaves as shelter. Any non-toxic, aquarium-safe sea plants will fare well in a tank with Blennies. This fish does not usually eat plants, focusing solely on algae as its main source of food.

Note:
Coral is not a good option for Lawnmower Blennies. They tend to nibble on coral, which can be dangerous both for them and the other species in your tank. This can also kill your coral off quite quickly.

Water Conditions and Parameters

Water conditions should be perfect not only for the Lawnmower Blenny but for the growth of algae as well. Since Blennies eat different types of algae, you can encourage its growth by controlling the water a certain way.

Make sure you follow the below parameters for the health of your fish and its environment.

– Water Temperature

Since these fish are more used to warmer and more tropical conditions in the ocean, your water should be kept fairly warm. Anywhere between 72 – 78 °F (22 – 25.5 °C) should be suitable for your Blenny.

– Water pH Levels

Water that is fairly high in acidity will work well for the Lawnmower Blenny. Make sure to maintain a balanced pH level between 8 – 8.5 at all times.

– Water Hardness

You should ensure that the hardness of the water stays between 8 – 12 dKH. This range allows you to be accommodating to other creatures that may be living in the tank as well.

You must change out at least a quarter of the tank’s water once a week to keep conditions clean. Too many algae and other floating matter can dirty the water, creating unsafe conditions for your underwater habitat. It is imperative to regularly monitor the state of your aquarium’s water.

Diet and Feeding

You will almost always see Lawnmower Blennies eating! This is one of the exciting parts of owning these fish that makes them interesting to watch. They graze on algae that grow on rocks and other places around the tank, using this naturally-occurring substance to feed themselves.

This is not only beneficial as it feeds the Blenny, but it also keeps your tank and water conditions clean. You don’t have to spend hours scraping all the algae off of the sides of the tank; just let the Blennies eat it for you. Make sure you don’t add a Blenny to your tank until some alga film has grown.

They will also hit the substrate with their mouths to stir up detritus, using this as another form of food.

What Does a Lawnmower Blenny Eat?

Lawnmower Blennies eat different forms of algae as their main source of food. Make sure there is a constant source of algae growing in the tank for them to feed on.

You should also supplement their diet with additional nutrients to keep them balanced and healthy. Make sure to give them:

• Fish eggs
• Detritus
• Diatoms
• Algae wafers/pellets
• Green vegetables

You should be growing enough algae for your Blennies to eat several times a week. If they are scraping the surface of the aquarium too frequently, they may not be getting enough to eat. Make sure to supply more algae to their tank if this is the case.

Will Lawnmower Blenny Eat Hair Algae?

Hair algae are one of the most common types of algae that you will find Blennies eating. Although, every fish has a different taste, and some may prefer other types of algae.

For the most part, you can expect this kind of algae to be eaten regularly by Lawnmower Blennies.

Will Lawnmower Blenny Eat Red Algae?

In the wild, Lawnmower Blennies eat a wide variety of algae. This includes Filamentous algae like green, red, and brown. It is very likely that your fish will enjoy eating red algae, which is one of the safest types of algae for them to eat.

You can’t go wrong with most types of algae. However, Lawnmower Blennies are not very keen on Cyanophytes, such as blue-green algae.

Does Lawnmower Blenny Eat Seaweed?

These Blenny species do not usually eat a lot of seaweed, but this is not an unsafe thing for them to eat. In fact, if you are trying to get your Blennies accustomed to a new tank with algae that is still growing, some seaweed and nori flakes will help them start to graze.

They can also eat seaweed as a supplement to their regular algae diets.

Will Lawnmower Blenny Eat Diatoms?

Diatoms are single-celled algae such as plankton and other tiny organisms. Diatoms are often fished out of the bottom of the tank by Lawnmower Blennies as a nutritional snack.

This is one of the Lawnmower Blenny’s favorite things to eat aside from the algae that they graze on throughout the day.

Lawnmower Blenny Diseases

It is not very difficult to keep your Lawnmower Blenny healthy and thriving. These are hardy fish that can usually tolerate small changes to the environment and water conditions. This fish is even tolerant of most common fish diseases.

But it is still important to be aware of the different diseases and illnesses that this fish is susceptible to. It is critical that you keep the aquarium clean on a regular basis to prevent these illnesses from occurring in any of your aquarium life.

Some common ailments and issues to be aware of include:

Infection

Dirty water makes all of the fish in your tank sick. When you don’t act quickly to get rid of water pollution, even hardy fish like the Lawnmower Blenny cannot survive for very long in toxic conditions. This can lead to severe infection.

Stress

Poor water quality can also cause your fish to become stressed out, making them susceptible to weakness. But before treating your sick fish with medication, make sure you are investing in something that does not hurt scaleless fish like the Lawnmower Blenny.

Gender Differences of Lawnmower Blenny

It is quite difficult to sex Lawnmower Blennies. There are almost no distinguishable differences between males and females of this subspecies, although some experts claim that males can become slightly larger than females. A few males also have elongated rays on their anal fins.

If you plan on keeping multiples in your tank, you should have an even number of males and females to avoid aggression within the species. For the most part, these fish survive on their own, so you don’t have to worry about setting up the perfect breeding conditions.

Breeding the Lawnmower Blenny

Lawnmower Blennies are very picky about their mates. Even if you own a female and a male, they may not be attracted to each other. It takes a lot for  Blennies to want to mate, which is why most aquarists have trouble breeding Lawnmower Blennies at home.

Keeping a healthy and comfortable environment is the key to getting your Blennies to mate. You might want to clean the tank more often during the mating season if you are trying to breed them on your own. They should also be given a full and healthy diet to keep their energy levels high.

Lawnmower Blenny Tank Mates

There is a variety of colorful saltwater fish of all shapes and sizes that will make excellent tank mates for your Lawnmower Blenny. They are mostly peaceful fish species and can get along easily with other species.

There may be some aggression amongst their own kind, but that shouldn’t be a problem with the rest of the creatures in the tank.

There is a group of fish that you should not keep with Lawnmower Blennies under any circumstances:

• Other Blenny species
• Other Lawnmower Blennies (unless it is one male and one female)
• Algae eaters
• Seahorses
• Groupers
• Lionfish
• Damselfish

You should also not keep any fish that is much larger than the Blenny, as they might eat your smaller fish. As long as you keep your tank in good conditions with plenty of space for your Blenny to establish a territory, you should have an easy time adding this fish to a habitat that already has others in it.

Can You Have 2 Blennies in a Tank or More?

The Lawnmower Blenny usually lives on its own and prefers to stay that way. Too many of them in the same tank could cause aggression, especially when you have two males or two females together.

At most, you can have one female and one male. You will do just fine with one Lawnmower Blenny as well.

Are Lawnmower Blennies Hardy?

The Lawnmower Blenny is incredibly hardy, making it one of the easiest saltwater fish to care for. Living amongst the rocks and eating algae makes it tough both on the inside and the outside, keeping it free from most common diseases and conditions.

You should still maintain a healthy environment and clean tank conditions for the betterment of your fish’s health.

Are Lawnmower Blennies Fin Nippers?

Under extreme stress, or when exposed to multiple members of its own species, the Lawnmower Blenny will become aggressive. They will attack other fish, nipping at their fins and their bodies.

In most cases, this does not do any serious damage and should not be any cause for concern.

Are Lawnmower Blennies Aggressive?

Lawnmower Blennies only become aggressive when they are stressed or cramped in their environment. They are known to fight off other members of their species over territory or mates.

As long as your aquarium is kept clean and you have enough algae to sustain the life and health of your Lawnmower Blenny, there shouldn’t be any cause for aggression.

Final Thoughts of Keeping a Lawnmower Blenny

If you are looking to diversify your saltwater aquarium with fun and hardy fish, the Lawnmower Blenny is a great fish to start with.

These curious fish will follow you around and stem the tide of algae growing in their tank. This is an attractive and popular species that will keep your underwater habitat thriving and vibrant with life.

If you feel comfortable taking care of Lawnmower Blenny by reading this article, please let us know your comments below.