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Marine Betta
Basslet

Marine Betta

Calloplesiops altivelis

A slow, elegant, deep-brown fish stippled with white spots and trailing long unpaired fins, famous for the false eyespot near its tail that lets it back into a crevice and mimic the head of a moray eel. It is peaceful and completely coral-safe, but make no mistake — it is an ambush predator that will inhale any fish or shrimp small enough to fit its surprisingly large mouth. Wild fish can be stubborn feeders, so a captive-bred specimen already weaned onto prepared food is a far easier fish. Nocturnal and retiring; give it caves, dim corners and no bite-sized tankmates.

Temperament
Peaceful
Max size
7.9"
Min tank
55 gal
Reef-safe
Reef safe
Diet
Carnivore
Zone
Caves, Rockwork, Bottom
Keep just one per tank — two will fight.
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Tankmates

How Marine Betta 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.

Percula ClownfishMarine Betta has a big enough mouth to eat the much smaller Percula Clownfish.Banggai CardinalfishMarine Betta has a big enough mouth to eat the much smaller Banggai Cardinalfish.Pajama CardinalfishMarine Betta has a big enough mouth to eat the much smaller Pajama Cardinalfish.Green ChromisMarine Betta has a big enough mouth to eat the much smaller Green Chromis.Blue DamselMarine Betta has a big enough mouth to eat the much smaller Blue Damsel.Yellowtail DamselMarine Betta has a big enough mouth to eat the much smaller Yellowtail Damsel.Helfrich's FirefishA 6 cm firefish fits the Betta’s gape; firefish are named among fish this ambush predator swallows overnight.Yasha GobyA 5 cm shrimp goby is well within gape; the Betta hunts small bottom fish at night while they rest.Tailspot BlennyMarine Betta has a big enough mouth to eat the much smaller Tailspot Blenny.McCosker's Flasher WrasseMarine Betta has a big enough mouth to eat the much smaller McCosker's Flasher Wrasse.Sixline WrasseMarine Betta has a big enough mouth to eat the much smaller Sixline Wrasse.Lubbock's Fairy WrasseMarine Betta has a big enough mouth to eat the much smaller Lubbock's Fairy Wrasse.Royal GrammaMarine Betta has a big enough mouth to eat the much smaller Royal Gramma.Chalk BassMarine Betta has a big enough mouth to eat the much smaller Chalk Bass.Orchid DottybackMarine Betta has a big enough mouth to eat the much smaller Orchid Dottyback.Springer's DottybackMarine Betta has a big enough mouth to eat the much smaller Springer's Dottyback.Purple DottybackMarine Betta has a big enough mouth to eat the much smaller Purple Dottyback.Mandarin DragonetMarine Betta has a big enough mouth to eat the much smaller Mandarin Dragonet.Purple FirefishAn 8 cm firefish is slender enough to be taken by the Betta’s large gape at night.FirefishAn 8 cm firefish is a documented Betta prey type; slender and often at rest in the open at night.