Jeweled Blenny

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Easy to Feed


Easy Environment Needs


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Jeweled/Lawnmower Blenny - Habit, Diet, and Selection


Pennsylvania, United States

Posted Feb 02, 2009

The jeweled blenny is a small, popular algae-grazing fish. Its name reflects its appearance for, while it is generally a banded brown/tan appearance, tiny sparkling spots appear along its back (between the dorsal fins and midline) and around its eyes, like tiny jewels lining its body. 

Attaining a length of about 5 inches in the home aquaria, this species has been nicknamed the "lawnmower blenny" for its seemingly-endless appetite for filamentous algal species, such as nuisance hair algae. They are on the move frequently, using their uniquely-shaped mouths to scrape algae off of the rockwork and the glass. As long as other animals aren't aggravating the blenny, they get along just fine with other species, including invertebates.

In my experience, this pet has not required supplemental feeding. In a 75 gallon tank, I have never had to add algae sheets to the tank. There always seems to be just enough "trace" algae along the rocks and glass to feed the blenny, despite the presence of 6 astrea snails that have the same diet.

This fish does not have a swim bladder, but its pectoral fins have been modified it to permit "perching" behavior on rocks and substrate. They will often find a quiet place to hide, carefully watching the surroundings for any stimuli. As a result, your blenny will appreciate rock work, especially with a large amount of nooks and crannies to hide in. When they grow accustomed to the aquarist, they will frequently perch or feed in plain sight, hiding during the night or when new people enter the room.

When considering this species at a shop, make sure he's keenly aware of his surroundings, including you. These fish are defenseless against carnivorous fish, so they rely on sharp senses, including vision, to avoid predation. Also watch to make sure that the blenny is actively "sampling" objects in the tank for food...they are gluttons, and if a member isn't hungry, something is very wrong. Finally, blennies are scaleless, and use copious amounts of slime, which is good for avoidig parasites, but can be troublesome if they haven't been handled carefully. You can check this by observing the undersides and fins for any reddening...if this has happened, don't buy the specimen.

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