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Forktail Blenny
Blenny

Forktail Blenny

Meiacanthus atrodorsalis

The most widely kept fang blenny — a lavender-blue head washing into a yellow rear and a deeply forked tail, with a black stripe through the eye. It hovers in midwater instead of perching, and its venomous bite means larger fish generally ignore it, so it stays visible and unbothered in a mixed community. Reef safe and invert safe, hardy, and now widely available captive bred, which makes it one of the easier small fish to start with. Keep one per tank unless you buy an established pair, and cover the tank — Meiacanthus jump.

Temperament
Semi-aggressive
Max size
4.3"
Min tank
30 gal
Reef-safe
Reef safe
Diet
Omnivore
Zone
Mid-water, Open water, Rockwork
Keep just one per tank — two will fight.
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Tankmates

How Forktail Blenny gets on with the rest of the reef, checked pair by pair by the same engine as the live pre-flight.

Best kept apart

A real clash — aggression, predation or a same-genus fight.

Canary BlennyBoth are Meiacanthus fang blennies of near-identical shape and size. Two males will feud continuously in anything under about 75 gallons, with the dominant one harassing the other into a corner.Picasso TriggerfishPicasso Triggerfish has a big enough mouth to eat the much smaller Forktail Blenny.Dragon WrasseDragon Wrasse has a big enough mouth to eat the much smaller Forktail Blenny.Volitans LionfishVolitans Lionfish has a big enough mouth to eat the much smaller Forktail Blenny.Snowflake MoraySnowflake Moray has a big enough mouth to eat the much smaller Forktail Blenny.Zebra MorayZebra Moray has a big enough mouth to eat the much smaller Forktail Blenny.Chainlink MorayChainlink Moray has a big enough mouth to eat the much smaller Forktail Blenny.Golden Dwarf MorayGolden Dwarf Moray has a big enough mouth to eat the much smaller Forktail Blenny.Rectangle TriggerfishRectangle Triggerfish has a big enough mouth to eat the much smaller Forktail Blenny.Clown TriggerfishClown Triggerfish has a big enough mouth to eat the much smaller Forktail Blenny.Miniata GrouperMiniata Grouper has a big enough mouth to eat the much smaller Forktail Blenny.Panther GrouperPanther Grouper has a big enough mouth to eat the much smaller Forktail Blenny.Six-Line SoapfishSix-Line Soapfish has a big enough mouth to eat the much smaller Forktail Blenny.Painted FrogfishPainted Frogfish has a big enough mouth to eat the much smaller Forktail Blenny.Dogface PufferDogface Puffer has a big enough mouth to eat the much smaller Forktail Blenny.Porcupine PufferPorcupine Puffer has a big enough mouth to eat the much smaller Forktail Blenny.Spanish HogfishSpanish Hogfish has a big enough mouth to eat the much smaller Forktail Blenny.Smith's BlennyForktail Blenny and Smith's Blenny are the same genus (Meiacanthus) and will fight — keep only one.Striped Poison Fang BlennyForktail Blenny and Striped Poison Fang Blenny are the same genus (Meiacanthus) and will fight — keep only one.

Keep an eye on these

Usually fine, but worth watching in a smaller tank.

Maroon ClownfishForktail Blenny and Maroon Clownfish both claim the same part of the tank and may squabble.Blue DamselForktail Blenny and Blue Damsel both claim the same part of the tank and may squabble.Yellowtail DamselForktail Blenny and Yellowtail Damsel both claim the same part of the tank and may squabble.Flame AngelfishForktail Blenny and Flame Angelfish both claim the same part of the tank and may squabble.Coral Beauty AngelfishForktail Blenny and Coral Beauty Angelfish both claim the same part of the tank and may squabble.Lemonpeel AngelfishForktail Blenny and Lemonpeel Angelfish both claim the same part of the tank and may squabble.Bicolor AngelfishForktail Blenny and Bicolor Angelfish both claim the same part of the tank and may squabble.Red Saddleback ClownfishForktail Blenny and Red Saddleback Clownfish both claim the same part of the tank and may squabble.Yellow TangForktail Blenny and Yellow Tang both claim the same part of the tank and may squabble.Red Sea ClownfishForktail Blenny and Red Sea Clownfish both claim the same part of the tank and may squabble.Sailfin TangForktail Blenny and Sailfin Tang both claim the same part of the tank and may squabble.Purple TangForktail Blenny and Purple Tang both claim the same part of the tank and may squabble.Powder Blue TangForktail Blenny and Powder Blue Tang both claim the same part of the tank and may squabble.Matted FilefishForktail Blenny and Matted Filefish both claim the same part of the tank and may squabble.Midas BlennyTwo slender, similarly sized blennies that both claim a rock hole and hover above it. The Midas in particular turns territorial toward fish of its own build.Yellow Clown GobyForktail Blenny (semi-aggressive) is much larger than the peaceful Yellow Clown Goby and may harass it.Green Clown GobyForktail Blenny (semi-aggressive) is much larger than the peaceful Green Clown Goby and may harass it.Convict TangForktail Blenny and Convict Tang both claim the same part of the tank and may squabble.Clark's ClownfishForktail Blenny and Clark's Clownfish both claim the same part of the tank and may squabble.Tomato ClownfishForktail Blenny and Tomato Clownfish both claim the same part of the tank and may squabble.