The Lawnmower Blenny (Salarias fasciatus), also known as the Jewelled Blenny or Rock Skipper, is a saltwater utility fish that is used as part of a clean up crew to keep hair algae at a minimum. In our opinion, using this fish as a means of controlling algae should only be considered as a short-term fix to a bigger issue. Accumulating nutrients that feed the algae growth need to be diluted through better aquarium husbandry. The lawnmower blenny will hop from rock to rock rasping at the algae growth and they do a great job on "hair algae". However, once this algae is reduced supplemental feeding may become necessary to prevent starvation.
They can usually be purchased locally or online anywhere from $10 to $20 US dollars. They do ship well but buying one sight unseen can be risky. Use a local supplier as your first option.

This blenny is quite endearing and has a very curious personality. They may remind you of an iguana or similar lizard the way they look at you with those orbital eyes. A healthy and well adapted specimen will be very aware of it's surroundings and observant of other fish and the aquarium keeper. If you walk by the tank while they are eating, they will stop and take notice of you for a bit and then continue on with what they were doing. Very cool little fish.

Use caution if you plan on keeping one of these lawnmowers 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. Obviously, you don't want to keep them with much larger species either that may view them as food (Lionfish, Triggers, etc.). Nipping at coral polyps and clam mantles is sometimes reported, so again, use caution if you have a reef tank and be prepared to remove them if this becomes a problem. Since they like to stay around the live rock removing them can be quite difficult. A fish trap may be necessary in this case. Author Scott Michael advises not to keep these Jewelled Blennies with seahorses and pipefishes "which it will harass".