Can black ghost knives live with chinese algae eaters?

Verdict
Yes

Yes. Black ghost knives and chinese algae eaters make a good pair. Both are fine at 74–80°F. Plan on at least 125 gal.

Black ghost knifeBlack ghost knife73–82°F · pH 6–8 Chinese algae eaterChinese algae eater74–80°F · pH 6–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 74–80°Black ghost knife 73–82°Chinese algae eater 74–80°
The green band is the temperature range both can live in.
456789Both: 6–8Black ghost knife 6–8Chinese algae eater 6–8
The green band is the pH both tolerate.

Size to scale

Black ghost knife · 15 inChinese algae eater · 10 in0"2"4"6"8"10"12"14"
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 knifeChinese algae eater
Temperature73–82 °F74–80 °F
pH6–86–8
Adult size15.0 in10.0 in
Minimum tank125 gal75 gal
TemperamentSemi-aggressiveSemi-aggressive
Swims atBottomBottom
GroupOne per tankAlone or in pairs
DietCarnivoreHerbivore

Better tank mates for black ghost knives

All black ghost knife tank mates

Better tank mates for chinese algae eaters

All chinese algae eater tank mates

Questions

Can black ghost knives live with chinese algae eaters?

Yes. Black ghost knives and chinese algae eaters make a good pair. Both are fine at 74–80°F. Plan on at least 125 gal.

What temperature suits both black ghost knives and chinese algae eaters?

74–80 °F. Black ghost knives need 73–82 °F, chinese algae eaters need 74–80 °F.

What size tank do black ghost knives and chinese algae eaters need together?

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