Can peacock cichlids live with black ghost knives?

Verdict

No. Peacock cichlids and black ghost knives should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 6 inches peacock cichlids do.

Peacock cichlid76–82°F · pH 7.8–8.6

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 6 inches peacock cichlids do.

What works

Both are fine at 76–82°F.
pH 7.8–8 suits both.
They use different parts of the tank: peacock cichlids the mid, black ghost knives the bottom.

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

	Peacock cichlid	Black ghost knife
Temperature	76–82 °F	73–82 °F
pH	7.8–8.6	6–8
Adult size	6.0 in	15.0 in
Minimum tank	55 gal	125 gal
Temperament	Semi-aggressive	Semi-aggressive
Swims at	Middle	Bottom
Group	Groups of 4+	One per tank
Diet	Carnivore	Carnivore

Better tank mates for peacock cichlids

All peacock cichlid tank mates

Better tank mates for black ghost knives

All black ghost knife tank mates

Questions

Can peacock cichlids live with black ghost knives?

No. Peacock cichlids and black ghost knives should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 6 inches peacock cichlids do.

What temperature suits both peacock cichlids and black ghost knives?

76–82 °F. Peacock cichlids need 76–82 °F, black ghost knives need 73–82 °F.

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

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