Can convict cichlids live with black ghost knives?

Verdict

No. Convict cichlids and black ghost knives should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 5 inches convict cichlids do.

Convict cichlid74–82°F · pH 6.6–7.8

Black ghost knife73–82°F · pH 6–8

What to watch

Deal breakerAn adult black ghost knife eats fish that fit in its mouth, and at 5 inches convict cichlids do.
Watch outConvict cichlids are aggressive. Black ghost knives hold their own only in a big tank with places to hide.
Watch outBlack ghost knives grow to 15 inches and need 125 gallons, far more than a tank set up for convict cichlids.

What works

Both are fine at 74–82°F.
pH 6.6–7.8 suits both.

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

	Convict cichlid	Black ghost knife
Temperature	74–82 °F	73–82 °F
pH	6.6–7.8	6–8
Adult size	5.0 in	15.0 in
Minimum tank	30 gal	125 gal
Temperament	Aggressive	Semi-aggressive
Swims at	Bottom	Bottom
Group	Alone or in pairs	One per tank
Diet	Omnivore	Carnivore

Better tank mates for convict cichlids

All convict cichlid tank mates

Better tank mates for black ghost knives

All black ghost knife tank mates

Questions

Can convict cichlids live with black ghost knives?

No. Convict cichlids and black ghost knives should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 5 inches convict cichlids do.

What temperature suits both convict cichlids and black ghost knives?

74–82 °F. Convict cichlids need 74–82 °F, black ghost knives need 73–82 °F.

What size tank do convict cichlids and black ghost knives need together?

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