Can black ghost knives live with clown plecos?

Verdict

No. Black ghost knives and clown plecos should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 3.5 inches clown plecos do.

Black ghost knife73–82°F · pH 6–8

Clown pleco73–82°F · pH 6.5–7.5

What to watch

Deal breakerAn adult black ghost knife eats fish that fit in its mouth, and at 3.5 inches clown plecos do.
Watch outBlack ghost knives grow to 15 inches and need 125 gallons, far more than a tank set up for clown plecos.

What works

Both are fine at 73–82°F.
pH 6.5–7.5 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

	Black ghost knife	Clown pleco
Temperature	73–82 °F	73–82 °F
pH	6–8	6.5–7.5
Adult size	15.0 in	3.5 in
Minimum tank	125 gal	20 gal
Temperament	Semi-aggressive	Peaceful
Swims at	Bottom	Bottom
Group	One per tank	Alone or in pairs
Diet	Carnivore	Herbivore

Better tank mates for black ghost knives

All black ghost knife tank mates

Better tank mates for clown plecos

All clown pleco tank mates

Questions

Can black ghost knives live with clown plecos?

No. Black ghost knives and clown plecos should not share a tank. An adult black ghost knife eats fish that fit in its mouth, and at 3.5 inches clown plecos do.

What temperature suits both black ghost knives and clown plecos?

73–82 °F. Black ghost knives need 73–82 °F, clown plecos need 73–82 °F.

What size tank do black ghost knives and clown plecos need together?

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