Pecking and scraping at powerhead for algae is actually normal. There is a misconception that they must have lots of algae to survive. Truth is . . . . . although a blenny needs plenty of algae to survive, a common misconception is that it can survive on algae alone. Since blennies frequent shallow tropical waters, they find their sanctuary within the coral reefs. They circle areas with coral branches and sponges, scraping their way along the diverse sea bottom. Their feeding techniques are to pound and gnaw the coral, and as a result, they ingest detritus, or waste material primarily, from the coral. This includes bits of coral skeleton, sand, gravel, and other organic matter, such as fish eggs and tiny crustaceans.
Since a blenny in the wild does not subsist on solely algae, it stands to reason that their captive diet must be supplemented.
