Lawnmower Blenny Care And Breeding Guide

The lawnmower Blenny is a very fascinating fish for an aquarium. Apart from its comical nature, it controls algae growth in the tank. Most hobbyists keep the fish to be entertained. In the process of enjoying its many comical displays, they also realize the tank’s algae growth is controlled to a minimum.

The fish is known by several other names including jeweled rock skipper, algae blenny, jeweled blenny and sailfin blenny. Scientifically, it is referred to as salarias fasciatus. The droll sea animal has been adopted as a home pet by several households to keep them entertained as it never runs out of great performances.

Lawnmower Blenny Fish

Appearance of Lawnmower Blenny

Considered a peaceful fish with great personality, this little sea animal has very unique features. One of the features are brown body color with white spots at given section of its profile. Some green can also be spotted on the fish. The dark color helps it in camouflage. If it patches on a brown rock, it becomes very difficult to notice it. It has long yet slender body. Other features of Lawnmower Blenny are:

  • A single dorsal fin that extends the whole length of its body
  • A blunt head with bulging eyes perched at the top. On the face are scattered blue dots that form some kind of artwork around the eyes
  • Extending from the pupils outward are white stripes that form a radial kind of pattern
  • It is about 4-6 inches in length
  • It lives between 2-4 years. When well taken care of in captivity, its lifespan may extend by another extra year


It is native of the East African Indian Ocean, Samoa, Red Sea, Great Barrier Reef and Islands of Micronesia. It obtained its name from its ability to clear algae from around its habitat.

In its natural habitat, lawnmower blenny enjoys swimming in shallow waters where there is little or no other sea life. They swim as a group around rocks.

Tank Requirements

The lawnmower blenny needs a huge tank that can provide a large area for algae growth. For this reason, the following tank requirements should be able to meet its needs:

  • A tank with not less than 30 gallons of water. If possible, a larger tank could be provided to give it ample room for swimming.
  • Plenty to moderate amounts of algae. Before introducing it into a tank, work on the algae growth by setting water conditions that will speed the growth. This can be done a few weeks before it is introduced into the aquarium.
  • Establish rocky areas within the tank by incorporating sizeable rocks on sand and gravel. If possible, the rocks could have holes within them to provide an ideal hiding place. Without a place to hide into, the lawnmower is likely to be stressed. Ensure the rockwork and substrate supports the microalgae growth.
  • Moderate to high water movement.
  • Keep temperatures at between 72 and 78 Fahrenheit.
  • Maintain a pH of 8.1-8.4.
  • Keep the lighting moderate. Avoid very bright lights.
  • Change the water in the tank occasionally to keep it in top form.
  • Add some plant life into the tank to give the aquarium a natural sea look. Most fish species are happier with an almost natural habitat. Ensure these (rocks and plants) are arranged towards the edge of the tank to provide sufficient space for swimming.


The fish is considered herbivore and will mainly feed on algae. In fact, most hobbyists add it to the aquarium to demolish algae build-up. It never disappoint in this. If the tank has no sufficient algae growth, some form of it (algae pellets) can be purchased as alternative. This will prevent it from starving. Add vegetables like lettuce and spinach to the tank. These can be chopped into tiny pieces that are easy to digest.

Nori is another marine algae supplement that can be added to its diet. Keep a bit of processed fish food too just in case. Although it tends to appreciate algae more, when this is lacking it settles for processed foods. To be successful, introduce the processed food to it as soon as it gets into its new environment. This will help it adjust to the new diet. Feed it once a day. Determine the amount of food it consumes every time food is brought to it.

Try to avoid stuffing too much food into the tank if there is no cleaner fish to clear away remnants. Most fish develop ich as a result of wasted food staying longer inside the tank. If possible, adopt a cleaner fish that will clear away any leftovers. Keep a close look at the fish. If there are signs of depreciating body size, try to keenly observe the diet.

While feeding, be careful with the tank lid as they are known to jump quite highly. If not properly fed, the fish claws at corals and may nip clams.


Lawnmower Blenny

Like a large number of other fish species, lawnmower blenny males and females look alike. Telling the difference between males and females is a difficult task. However, males are said to be bigger than their female counterparts.

The anal fins may also betray a small difference for a very keen observer. The male has bigger anal spines, packed with plenty of flesh as opposed to the female.

Not much has been reported on breeding the fish in captivity.

Social Behavior

The fish is described as relatively friendly. However, they may pick a fight with congeners, conspecifics and other same species fish. This happens more when the tank is small with a huge number of tank-mates.

It may also turn aggressive to sea horse or pipe fish. If they share the same tank, check them regularly if they are compatible. If any signs of aggressiveness are witnessed, they ought to be separated. They are known to recognize regular faces and may reward it with a few theatrics.

The lawnmower is a playful addition to a tank. When in need of a fish to provide some fun after a difficult day at the workplace, then the lawnmower blenny is it.

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