Can black ghost knives live with dwarf gouramis?

Verdict

No. Black ghost knives and dwarf gouramis should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 3 inches dwarf gouramis do.

Black ghost knife73–82°F · pH 6–8

Dwarf gourami72–82°F · pH 6–7.5

What to watch

Deal breakerAn adult black ghost knife eats fish that fit in its mouth, and at 3 inches dwarf gouramis do.
Watch outBlack ghost knives are much bigger and pushier than dwarf gouramis, which are slow and easy to bully at feeding time.
Watch outBlack ghost knives grow to 15 inches and need 125 gallons, far more than a tank set up for dwarf gouramis.

What works

Both are fine at 73–82°F.
pH 6–7.5 suits both.
They use different parts of the tank: black ghost knives the bottom, dwarf gouramis the top.

Water side by side

The green band is the temperature range both can live in.

The green band is the pH both tolerate.

Size to scale

Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

	Black ghost knife	Dwarf gourami
Temperature	73–82 °F	72–82 °F
pH	6–8	6–7.5
Adult size	15.0 in	3.0 in
Minimum tank	125 gal	10 gal
Temperament	Semi-aggressive	Peaceful
Swims at	Bottom	Top
Group	One per tank	Alone or in pairs
Diet	Carnivore	Omnivore

Better tank mates for black ghost knives

All black ghost knife tank mates

Better tank mates for dwarf gouramis

All dwarf gourami tank mates

Questions

Can black ghost knives live with dwarf gouramis?

No. Black ghost knives and dwarf gouramis should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 3 inches dwarf gouramis do.

What temperature suits both black ghost knives and dwarf gouramis?

73–82 °F. Black ghost knives need 73–82 °F, dwarf gouramis need 72–82 °F.

What size tank do black ghost knives and dwarf gouramis need together?

At least 125 gal, set by the black ghost knife. Add space for each extra fish.