Harptail Blenny (Meiacanthus mossambicus)

The Harptail Blenny (Meiacanthus mossambicus), also sold as the Mozambique Fangblenny or Lyretail Fangblenny, is the blenny for people who want a blenny that actually swims. Most blennies perch on rock and dart between hiding spots. This one hovers out in open water like a small wrasse, drifting mid-tank with its long forked tail trailing behind it, and it does this all day where you can see it. Soft olive to yellow with dark shoulder striping and that unmistakable harp-shaped tail. Browse the rest of our saltwater fish.

The reason it can afford to hang in open water is that it is venomous. Fangblennies in the genus Meiacanthus carry grooved fangs with a mild venom, and a predator that swallows one gets bitten from the inside and spits it straight back out. Reef fish learn this fast, so a Harptail cruises around unbothered by things that would eat a similar-sized goby.

Care Guide

• Tank size: 30 gallons and up with live rock. It uses open water, so give it some room to cruise rather than a rock-packed nano.
• Diet: omnivore with a fast metabolism. Feed small amounts two to three times a day rather than one big feeding. Frozen mysis, enriched brine, and a quality marine pellet or flake. A skinny fangblenny is an underfed one.
• Temperament: genuinely peaceful. It rarely bothers tankmates and its venom means tankmates rarely bother it. One per tank unless the system is large, since same-genus fangblennies will spar.
• Reef safe: yes, completely. It ignores corals, clams, and ornamental inverts.
• Water: 72 to 78°F, salinity 1.020 to 1.025, pH 8.1 to 8.4. Hardy and forgiving once settled.
• Handling: do not hand feed and do not handle it without gloves. The venom is not dangerous to people, but a bite still hurts.
• Lid recommended: like most active reef fish it can jump.

Specifications

Compatibility

Excellent in a peaceful reef community: clownfish, cardinalfish, gobies, wrasses, small tangs, and dottybacks such as our Orchid Dottyback. Safe with all inverts, including cleaner shrimp and cleanup crews.

The venom makes it unusually safe around larger fish, but do not take that as licence to house it with a lionfish or a big grouper. And keep only one Meiacanthus unless the tank is large, since they recognise each other as rivals.

Recommended Foods & Supplies

• SFBB Frozen Mysis Shrimp, the staple for small carnivorous reef fish
• Piscine Energetics 1 mm Saltwater Pellets for dry daily feeding
• Browse the full saltwater selection for tankmates and reef supplies

FAQ

Is it dangerous to me?
Not really. The venom is a defence against being swallowed and it is not medically significant to humans. It can still bite, so use a net rather than your hand and skip hand feeding.

Is it reef safe?
Completely. It leaves corals, clams, and ornamental shrimp alone.

Will bigger fish eat it?
Most learn not to. Predators that swallow a fangblenny get bitten inside the mouth and release it, so they are left alone far more than a fish this size normally would be. That is not a guarantee against a large predator, though.

Can I keep two?
Only in a large tank. Two fangblennies in a 30 gallon will pick at each other. One is the safe answer.

Does it eat algae like other blennies?
No. Despite the name it is not a grazer. It is an omnivore that feeds in the water column, so do not buy one to control algae. A Lawnmower Blenny is the fish for that job.