Grazed and Confused: Our Friend The Lawnmower Blenny

There are hundreds of species of fish that are available to the reef hobbyist when its time to go shopping for new tank residents. Having the right mix of fish ensures not only a balanced ecosystem, but also prevents your tank from becoming a gloves off survival of the fittest battleground.  This takes us to our friend the Sailfin or as it is more commonly known, Lawnmower Blenny (Salarias fasciatus).  What this fish lacks in good looks, it makes up in appetite and character.  A relatively inexpensive fish that can keep your tank sparkly clean.

What Makes This Fish Good for a Reef Tank?

The LMB is a tank favorite of ours around ReefNation and I believe we have at least one in every tank.  This fish is an expert at using its wide scraping mouth to keep our live rock free of all types of algae.  They can usually be seen with their distended bellies perching on a coral, keeping watch out for any new algae that might be popping up around the reef tanks.  The LMB has a pretty chill demeanor and will sometimes chase down and eat flake and pellet food, but this is the exception rather than the rule.

What Do These Fish Eat?

When keeping the LMB in a tank, the biggest requirement would be that there is enough live rock for them to constantly gum on. The scraping motion that their mouth performs probably means they get nutrition from many things including algae, diatoms, zooplankton, and anything else that happens to be stuck on a rock when they come mowing by. One thing that we have noticed as well is that within reason, all the gumming these fish do to the rock work seems to prevent cyano bacteria (red slime). Algae from being able to get a foothold. We say within reason because you cannot expect to stick a LMB in a cyano filled tank and expect anything to happen. At that point you will need to reevaluate your water chemistry.  If your tank conditions are dialed in, this fishes’ mouth action will certainly aid in keeping your tank and live rock clean and algae free.

Do you have a secret weapon against algae over growing your tank?