Can glass catfish live with black ghost knives?

Verdict

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

Glass catfish75–80°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 3 inches glass catfish do.
Watch outBlack ghost knives grow to 15 inches and need 125 gallons, far more than a tank set up for glass catfish.

What works

Both are fine at 75–80°F.
pH 6.5–7.5 suits both.
They use different parts of the tank: glass catfish 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

	Glass catfish	Black ghost knife
Temperature	75–80 °F	73–82 °F
pH	6.5–7.5	6–8
Adult size	3.0 in	15.0 in
Minimum tank	30 gal	125 gal
Temperament	Peaceful	Semi-aggressive
Swims at	Middle	Bottom
Group	Groups of 6+	One per tank
Diet	Carnivore	Carnivore

Better tank mates for glass catfish

All glass catfish tank mates

Better tank mates for black ghost knives

All black ghost knife tank mates

Questions

Can glass catfish live with black ghost knives?

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

What temperature suits both glass catfish and black ghost knives?

75–80 °F. Glass catfish need 75–80 °F, black ghost knives need 73–82 °F.

What size tank do glass catfish and black ghost knives need together?

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