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Threadfin Cardinalfish
Cardinalfish

Threadfin Cardinalfish

Zoramia leptacanthus

A small, near-transparent cardinalfish with a silvery-yellow sheen and bright blue rings around the eyes, usually found hovering in loose shoals over branching stony coral. Unlike most cardinalfish it genuinely schools and stays visible during the day, but only if you buy a real group — five or more — since single fish hide and fade into the rockwork. It is nocturnal by instinct, so give the group a ledge or cave to sit under and expect it to feed best on small frozen items rather than pellets at first. Completely peaceful and reef safe, and small enough to be an easy fit in a modest tank. The one risk is that it is easily out-fed by anything faster, so keep its tankmates equally calm.

Temperament
Peaceful
Max size
2.4"
Min tank
30 gal
Reef-safe
Reef safe
Diet
Carnivore
Zone
Mid-water, Rockwork
Best in a shoal of 5+.
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Tankmates

How Threadfin Cardinalfish 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.

Maroon ClownfishMaroon Clownfish (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Purple TangPurple Tang (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Coral HawkfishCoral Hawkfish (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Antennata LionfishAntennata Lionfish has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Picasso TriggerfishPicasso Triggerfish (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Royal DottybackThreadfin cardinalfish kept with dottybacks stay hidden through the day and miss out at feeding time. The royal dottyback is one of the most aggressive of them.Domino DamselDomino Damsel (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Marine BettaA 6 cm slender cardinalfish is within the Betta’s gape and a documented prey type.Dragon WrasseDragon Wrasse has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Volitans LionfishVolitans Lionfish has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Zebra Dwarf LionfishZebra Dwarf Lionfish has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Fuzzy Dwarf LionfishFuzzy Dwarf Lionfish has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Snowflake MoraySnowflake Moray has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Zebra MorayZebra Moray has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Chainlink MorayChainlink Moray has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Golden Dwarf MorayGolden Dwarf Moray has a big enough mouth to eat the much smaller Threadfin Cardinalfish.Rectangle TriggerfishRectangle Triggerfish (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Clown TriggerfishClown Triggerfish (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Miniata GrouperMiniata Grouper (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Panther GrouperPanther Grouper (aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.

Keep an eye on these

Usually fine, but worth watching in a smaller tank.

Yellow TangYellow Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Sailfin TangSailfin Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Powder Blue TangPowder Blue Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Red Coris WrasseRed Coris Wrasse (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Convict TangConvict Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Emperor AngelfishEmperor Angelfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Regal AngelfishRegal Angelfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Achilles TangAchilles Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Naso TangNaso Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Scopas TangScopas Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Keyhole AngelfishKeyhole Angelfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Queen AngelfishQueen Angelfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Blueface AngelfishBlueface Angelfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Chevron TangChevron Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Mimic TangMimic Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Powder Brown TangPowder Brown Tang (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Square AnthiasSquare Anthias (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Blue-Throat TriggerfishBlue-Throat Triggerfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Crosshatch TriggerfishCrosshatch Triggerfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.Niger TriggerfishNiger Triggerfish (semi-aggressive) is much larger than the peaceful Threadfin Cardinalfish and may harass it.