Feeding
The Lawnmower Blenny is chiefly vegetarian and will feed by using its teeth (it is a so called combtooth blenny) to scrape algae off rocks and other surfaces in the aquarium. They are famous for eating hair algae, but are even fonder of film algae. Some specimens never touch hair algae.
If there isn’t a lot of algae in your aquarium, or if you have only one type of algae, it can be a good idea to supplement the natural algae growth with other types of food to ensure a varied and nutritious diet. You can for instance give your fish dried or frozen food for herbivore and algaevore fish. Occasional servings of bloodworms and similar meaty foods are appreciated and beneficial, but should not be offered too frequently or in large quantities.
Never place a Lawnmower Blenny in an aquarium where there aren’t a lot of algae and expect it to survive on the food you give it only. The recommendation above to supplement with other food is for blennies that already display a healthy appetite in the aquarium but are so efficient eaters that the algae can’t grow fast enough for them.
It can be hard to get your Lawnmower Blenny to eat when it arrives to its new home. Keep the water quality supreme and make sure that all aspects of your aquarium are suitable for the blenny. Avoid purchasing specimens that do not graze algae in the fish store and pass up specimens with pinched flat stomachs. Heavy breathing and a mouth that gapes wide open is another sign of starvation.
If you are an experienced and dedicated fish keeper with a good portion of luck you might be able to nurse a starving Lawnmower Blenny back to health by placing it in a quarantine aquarium with plenty of natural algae growth and slowly encourage it to start eating again.