From ReefPedia

[edit] Lawnmower Blenny Scientific Name Salarias fasciatus Max. Size: 5 to 6 inches Tank Size: 35 gallon with well established algal growth Aggression: This fish is rarely aggressive to its tankmates Hardiness: Relatively hardy as long as it is getting enough food (see below). Reef-Safe: Yes. This fish will not harm corals. Available as captive-bred: Yes

Lawnmower Blenny, Salarias fasciatus

Physical Description

Various shades of brown, white and black. Beak-like mouth structure.

Distribution

Indo-Pacific

Taxonomic Stuff you know you Care About

• Family: Blennidae

• Genus: Salarias

Can be fresh water fish.

• Species: Fasciatus

This fish eats everything.

Behavior

At night this fish may bury itself into the substrate leaving only its eyes visible, usually in the same spot each night. Other Blennies prefer to hide in a crevice on a rock at night. During the day it usually swims around the substrate and rockwork searching for food, often staring at and fighting with itself in the reflection of the glass (LM Blenny "war dance").

Feeding

It will eat frozen food sometimes, but not often enough to survive off of. You need to make sure that there is enough food in the tank in the form of common brown algae for it to graze on through out the day. Furthermore, some Lawnmower Blennies flat-out refuse to eat in captivity leading to the slow process of an aquarist watching a fish starve to death.

To avoid this scenario, it is Highly Recommended that the aquarist observe the fish eating at the fish store before purchasing it. You can almost always see mouth marks on the brown algae in the LFS holding tanks. This is a good sign that its a good specimin. If its stomach is pinched flat, there is a high chance it is refusing to eat, and is therefore not recommended.

Many of this species will learn to love the brown algae that grows on the glass. It is best to leave the back wall un scraped, giving them a backup food source, if they completely clean all other rock surfaces.

Breeding

Not known to breed in captivity.

Social Structure

May be aggressive if multiple specimens are kept together in a smaller tank. One per tank is recommended for tanks under 75 gallons.

Current Views

A goofy, endearing little fish with a great personality, Lawnmower Blennies are reef-safe, generally non-aggressive, and love to eat hair algae. As long as you find one that will eat in captivity, it will make a hardy and welcome addition to your tank.

FAQ

Q: My Blenny is breathing heavy and his mouth is staying open. Is something wrong?

A: If a Blenny isn't eating and the body thins, the mouth will start to gape open. If you notice that your LM Blenny's mouth is staying open in a wide oval shape (more than the usual slitted opening of a healthy Blenny's mouth), it may be best to try to quarantine it in order to encourage eating in the controlled environment.

Q: Will LM Blennies eat hair algae?

A: There are mixed reports on this. Some have reported that their Blennies "mow down" hair algae although there are just as many opposing reports stating that they won't touch it. If you have a hair algae problem and are lucky enough to have a Blenny that eats it, keep in mind that, with proper water care and feeding habits, your hair algae problem should one day go away and the Blenny might be left with Nori as the only food of choice. In instances where a tank has become "algae free", keep an eye on your Blenny to ensure that it is getting enough food via Nori and other small foods if applicable (some will eat dry food pellets). It may be a good idea to soak Nori stips in vitamin supplements before adding them to the tank.