Can bristlenose plecos live with black ghost knives?

Verdict

No. Bristlenose plecos 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 bristlenose plecos do.

Bristlenose pleco73–81°F · pH 6.5–7.5

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 bristlenose plecos do.
Watch outBlack ghost knives grow to 15 inches and need 125 gallons, far more than a tank set up for bristlenose plecos.

What works

Both are fine at 73–81°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

	Bristlenose pleco	Black ghost knife
Temperature	73–81 °F	73–82 °F
pH	6.5–7.5	6–8
Adult size	5.0 in	15.0 in
Minimum tank	30 gal	125 gal
Temperament	Peaceful	Semi-aggressive
Swims at	Bottom	Bottom
Group	Alone or in pairs	One per tank
Diet	Herbivore	Carnivore

Better tank mates for bristlenose plecos

All bristlenose pleco tank mates

Better tank mates for black ghost knives

All black ghost knife tank mates

Questions

Can bristlenose plecos live with black ghost knives?

No. Bristlenose plecos 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 bristlenose plecos do.

What temperature suits both bristlenose plecos and black ghost knives?

73–81 °F. Bristlenose plecos need 73–81 °F, black ghost knives need 73–82 °F.

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

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