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Lawnmower Blenny Care & Info

The peaceful Salarias fasciatus is a favorite among marine aquarists for its appetite for algae. Also known as the lawnmower blenny, it doesn’t exclusively eat algae, but it certainly consumes enough to be quite helpful!

Want to learn more about this bottom-dwelling underwater gardener? Keep reading for everything you need to know about the lawnmower blenny!

Name (Common, Scientific)Lawnmower blenny, sailfin blenny, algae blenny, Salarias fasciatus
Minimum tank size30 gallons
Minimum group sizeRecommended solitary
Temperature72-78 °F
Difficulty levelEasy

Lawnmower Blenny (Salarias fasciatus) Description

Naturally found in shallow tropical waters, Salarias fasciatus is a bit less brightly colored than some of its cousins, such as the scooter blenny. It features a more camouflage-like green-brownish pattern with vertical barring and a slightly darker horizontal stripe across its side.

At a maximum size of around 5”, the lawnmower blenny is not a particularly large fish. Telling the difference between males and females of this species can be rather challenging, although the females are often a bit larger and rounder.

Lawnmower blenny, Salarias fasciatus marine fish

Lawnmower Blenny Aquarium

You don’t need a large marine aquarium at all to house a single lawnmower blenny: 30 gallons should be a good size to start with, although you could always go bigger.

Although we’re often inclined to keep our aquariums nice and clean, this changes if you want to keep an algae eater. Your lawnmower blenny likes plenty of film algae (and sometimes hair algae) to snack on, so consider leaving some patches and tufts for it if any pops up.

Plenty of hides are a must. Lawnmower blennies are naturally prey fish and they like to dart into a cave or hide if they happen to feel threatened while foraging.

Lawnmower Blenny Compatibility

The lawnmower blenny is a peaceful fish that can be combined with a variety of other community fish as long as they’re not overly docile. Just as long as they are not or do not look too much like another lawnmower blenny, that is: the species is quite territorial.

If you’d like to keep of these blennies multiple in the same aquarium, prepare to go above and beyond the 30-gallon minimum tank size mentioned earlier. Even other blennies can be a risky choice, so if you’re an inexperienced fishkeeper you might want to stick with just the lawnmower.

Unfortunately lawnmower blennies can’t be considered 100% reef safe as they do get slightly nippy. This applies to polyps as well as clams, which they can become particularly interested in if their normal diet is lacking. Avoid them if you want to keep your tank an entirely nip-free zone.

lawnmower blenny

Caring for Lawnmower Blenny (Salarias fasciatus)

The most important aspect of keeping your blenny happy and healthy is catering to its diet. Leaving some “lawn” for it to mow is very helpful, although you’ll usually still have to supplement your blenny’s diet. If the belly of your fish seems caved in rather than round, it’s definitely time to make sure it’s getting enough nutrients!

Feed the lawnmower blenny algae-based foods specially formulated for herbivores, such as pellets or gel foods containing plenty of spirulina. You could also opt for blanched veggies like peas and spinach or nori seaweed sheets. Really dedicated lawnmower blenny owners could even grow algae in a separate container by keeping rocks under strong lighting to stimulate the growth of this aquatic delicacy!

Do keep in mind that blennies that are used to frequent feedings with convenient foods might be less inclined to go after algae. You shouldn’t be buying a fish to deal with an algae problem anyway, as keeping the aquarium clean is unfortunately up to you.


The lawnmower blenny is a fun and useful addition to the small marine aquarium. Dreaming of your own reef (with or without lawnmower)? FantaSEA Aquariums can help; just contact us here with your ideas and we’ll get back to you as soon as possible.

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Marijke Puts

Hey! I'm Marijke, FantaSEA's resident blog writer. I'm a full-time pop science author, part-time PADI diver and snorkeler, and have been keeping fish since I was a kid. When I'm not writing fish care guides, you can usually find me underwater or trying to figure out how to fit more tanks into my house.

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