Mr. Personality: The Lawnmower Blenny

by | Dec 15, 2014 | Fish | 1 comment

LawnmowerBlennyWhen I first got into reefing I had no idea where to start when it came time to get my first fish. After a lot of study, research and forum browsing I started to understand more about the fish themselves and which ones would get along together. For my first post I would like to talk more about the different fish newbie to the saltwater hobby can look at getting as their first fish.

The Lawnmower Blenny (Salarias fasciatus), is a saltwater utility fish that is used as part of a clean up crew to help keep hair algae at a minimum. In my opinion, using the Lawnmower Blenny as a means of controlling algae should only be considered as a short-term fix to a bigger issue. The lawnmower blenny will hop from rock to rock chomping at the algae growth and they tend to do a great job on “hair algae”. Once the hair algae is gone you will want to ensure they are fed using dried algae (nori), flake food and mysis shrimp.

The Lawnmower Blenny is quite engaging with a very curious personality. I have spoke with aquarists who have said they remind them of an iguana or similar lizard the way they look at you with those orbital eyes. I have also spoke with some who call them the dog’s, man’s best friend, of the saltwater tank. A healthy and well adapted specimen will be very aware of it’s surroundings and observant of other fish and also of the aquarium keeper. Simply walking by the tank while they are eating or swimming around, they will stop and take notice of you and then continue on with what they were doing. Very cool little fish.
Use caution if you plan on keeping one of these lawnmower blennies in a reef tank setup. They have been reported to become more aggressive as they grow and will not tolerate same or similar species in smaller tanks. It has also been said that they may nip at coral polyps and clam mantles. Althought I have not experienced this issue myself, use caution if you have a reef tank and be prepared to remove them if this becomes a problem. Since the Lawnmower Blenny likes to stay around the live rock, removing them can be quite difficult. You may want to look at getting a fish trap just in case you may need to remove the blenny for any reason.


  • Scientific Name : Salarias fasciatus
  • Common Names : Lawnmower Blenny, Algae Blenny, Jewelled Rockskipper Blenny, Rock Blenny
  • Care Level : Easy
  • Size : 4 – 6 inches
  • pH : 8.2 – 8.4
  • Temperature : 70°F – 82°F (21°C – 28°C)
  • Specific Gravity : 1.020 – 1.025
  • Carbonate Hardness (dKH) : 8 – 12°
  • Origin / Habitat : Indo-Pacific, Red Sea, Great Barrier Reef
  • Temperament / Behavior : These blennies can be quite peaceful with most tank mates, but may get belligerent with similar looking species or it’s own species. They may get more aggressive with other tank mates as they mature.
  • Breeding : Egg layer – they lay eggs that are sticky and attached to the substrate. Can be difficult since they might be aggressive with their own species unless they are a mated pair. Getting the pair is the hard part.
  • Aquarium Size : 30 gallon minimum.
  • Reef Tank Compatible? : Yes. But as with any inhabitant keep an eye on the blenny to ensure you are not seeing any nipping at coral or clam mantles.
  • Diet / Foods : Hair algae of course, but they will also readily take flake food, mysis shrimp and brine shrimp.
  • Tank Region : Usually on, in or around the live rock or sand. They are known as rock skippers because of the way they kind of hop from rock to rock on the reef.
  • Gender : Hard to determine differences between male and female.

I hope you have enjoyed the information provided on this truly fascinating and comical fish. Once he is in your tank you will find that it doesn’t take long before he becomes your best friend.

Happy Reefing!

  • ReeferDave

    I have a long time love for coral reefs and reefing. I currently have 30 years experience total in saltwater and freshwater aquariums. Currently I live in Tennessee with my wife and son and currently work as a level 2 tech support coordinator for my job.

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1 Comment

  1. Ed Lent

    This was incredibly helpful because it was written in an experienced and real manner. This information was greatly appreciated. Thanks


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