Tank mates for black ghost knifefish

We checked black ghost knifefish against all 149 other species in our database for water temperature, pH, size, fin nipping, predation and aggression.

Good tank mates for black ghost knifefish include nerite snail, angelfish, oscar, assassin snail, ramshorn snail and malaysian trumpet snail. Avoid betta fish, bronze corydoras and cherry shrimp: black ghost knifefish can eat bettas: they're small enough to fit in its mouth once it's grown.

Black ghost knifefish: 24–28°C (75–82°F), pH 6.5–7.8, adult size 45 cm (17.7 in), minimum tank 125 gallons (473 L). Full black ghost knifefish care guide.

Check a full stocking plan

Good Compatible tank mates (29)

Shared water conditions and no known conflict. Still add fish slowly and watch them.

Caution Possible, with care (35)

These can work in the right setup, but there is a real risk. Read the reason first.

  • Bristlenose pleco · 20+ gal
    • Bristlenose pleco defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Common pleco · 150+ gal
    • Common pleco defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Dwarf gourami · 15+ gal
    • Black ghost knifefish may eat dwarf gouramis, especially young or small ones.
  • Amano shrimp · 10+ gal
    • Black ghost knifefish hunts shrimp. Larger amano shrimp sometimes survive, but expect losses.
  • Denison barb · 75+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
  • Discus · 75+ gal
    • Their temperature ranges barely overlap (only around 28–28°C).
  • Electric blue acara · 40+ gal
    • Electric blue acara defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Firemouth cichlid · 29+ gal
    • Firemouth cichlid defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Ghost shrimp · 10+ gal
    • Black ghost knifefish hunts shrimp. Larger ghost shrimp sometimes survive, but expect losses.
  • Kribensis · 29+ gal
    • Kribensis defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Kuhli loach · 20+ gal
    • Black ghost knifefish may eat kuhli loaches, especially young or small ones.
  • Pictus catfish · 75+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
  • Rainbow shark · 75+ gal
    • Rainbow shark defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Red-tail shark · 75+ gal
    • Red-tail shark defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Rosy barb · 29+ gal
    • Their temperature ranges barely overlap (only around 24–24°C).
    • One is a cold-water species and the other is tropical, so neither will be at its best.
    • Black ghost knifefish may eat rosy barbs, especially young or small ones.
  • Bamboo shrimp · 20+ gal
    • Black ghost knifefish hunts shrimp. Larger bamboo shrimp sometimes survive, but expect losses.
  • Bolivian ram · 29+ gal
    • Black ghost knifefish may eat Bolivian rams, especially young or small ones.
    • Bolivian ram defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Bumblebee catfish · 20+ gal
    • Black ghost knifefish may eat bumblebee catfish, especially young or small ones.
  • Clown pleco · 20+ gal
    • Black ghost knifefish may eat clown plecos, especially young or small ones.
  • Cockatoo cichlid · 20+ gal
    • Black ghost knifefish may eat cockatoo cichlids, especially young or small ones.
    • Cockatoo cichlid defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Congo tetra · 40+ gal
    • Black ghost knifefish may eat Congo tetras, especially young or small ones.
  • Dwarf orange crayfish · 10+ gal
    • Their temperature ranges barely overlap (only around 24–24°C).
    • One is a cold-water species and the other is tropical, so neither will be at its best.
    • Black ghost knifefish may attack small crustaceans like dwarf orange crayfish, especially after they molt.
  • Emerald green corydoras · 55+ gal
    • Black ghost knifefish may eat emerald green corydoras, especially young or small ones.
  • Giant danio · 55+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
  • Golden wonder killifish · 20+ gal
    • Black ghost knifefish may eat golden wonder killifish, especially young or small ones.
  • Panda garra · 29+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
    • Black ghost knifefish may eat panda garras, especially young or small ones.
  • Paradise fish · 20+ gal
    • Their temperature ranges barely overlap (only around 24–24°C).
    • One is a cold-water species and the other is tropical, so neither will be at its best.
    • Black ghost knifefish may eat paradise fish, especially young or small ones.
  • Rubber lip pleco · 29+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
    • Rubber lip pleco defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Scissortail rasbora · 55+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
  • Thai micro crab · 5+ gal
    • Black ghost knifefish may attack small crustaceans like Thai micro crabs, especially after they molt.
  • Turquoise rainbowfish · 29+ gal
    • Their temperature ranges barely overlap (only around 24–25°C).
  • Vampire shrimp · 20+ gal
    • Black ghost knifefish hunts shrimp. Larger vampire shrimp sometimes survive, but expect losses.
  • Zebra loach · 29+ gal
    • Black ghost knifefish may eat zebra loaches, especially young or small ones.
  • Zebra pleco · 20+ gal
    • Black ghost knifefish may eat zebra plecos, especially young or small ones.
    • Zebra pleco defends its patch of the bottom and may chase black ghost knifefish, which use the same area.
  • Thick-lipped gourami · 20+ gal
    • Black ghost knifefish may eat thick-lipped gouramis, especially young or small ones.

Avoid Bad tank mates (85)

  • Betta fish: Black ghost knifefish can eat bettas: they're small enough to fit in its mouth once it's grown.
  • Bronze corydoras: Black ghost knifefish can eat bronze corydoras: they're small enough to fit in its mouth once it's grown.
  • Cherry shrimp: Black ghost knifefish eats small shrimp like cherry shrimp.
  • Common goldfish: They need different temperatures: Black ghost knifefish 24–28°C (75–82°F), common goldfish 15–22°C (59–72°F).
  • Fancy goldfish: They need different temperatures: Black ghost knifefish 24–28°C (75–82°F), fancy goldfish 18–23°C (64–73°F).
  • Guppy: Black ghost knifefish can eat guppies: they're small enough to fit in its mouth once it's grown.
  • Neon tetra: Black ghost knifefish can eat neon tetras: they're small enough to fit in its mouth once it's grown.
  • Panda corydoras: Black ghost knifefish can eat panda corydoras: they're small enough to fit in its mouth once it's grown.
  • Tiger barb: Black ghost knifefish can eat tiger barbs: they're small enough to fit in its mouth once it's grown.
  • Zebra danio: Black ghost knifefish can eat zebra danios: they're small enough to fit in its mouth once it's grown.
  • African dwarf frog: Black ghost knifefish can eat African dwarf frogs.
  • Black skirt tetra: Black ghost knifefish can eat black skirt tetras: they're small enough to fit in its mouth once it's grown.
  • Cardinal tetra: Black ghost knifefish can eat cardinal tetras: they're small enough to fit in its mouth once it's grown.
  • Celestial pearl danio: Black ghost knifefish can eat celestial pearl danios: they're small enough to fit in its mouth once it's grown.
  • Cherry barb: Black ghost knifefish can eat cherry barbs: they're small enough to fit in its mouth once it's grown.
  • Chili rasbora: Black ghost knifefish can eat chili rasboras: they're small enough to fit in its mouth once it's grown.
  • Chinese algae eater: Chinese algae eater is aggressive and will bully or injure peaceful black ghost knifefish.
  • Convict cichlid: Convict cichlid is aggressive and will bully or injure peaceful black ghost knifefish.
  • Dojo loach: They need different temperatures: Black ghost knifefish 24–28°C (75–82°F), dojo loach 18–23°C (64–73°F).
  • Dwarf neon rainbowfish: Black ghost knifefish can eat dwarf neon rainbowfish: they're small enough to fit in its mouth once it's grown.
  • Electric yellow cichlid: Electric yellow cichlid is a Lake Malawi cichlid. It needs a Lake Malawi tank: hard, alkaline water (pH 7.5–8.5), plenty of rockwork and other cichlids from the same lake. Black ghost knifefish don't belong in that setup.
  • Ember tetra: Black ghost knifefish can eat ember tetras: they're small enough to fit in its mouth once it's grown.
  • German blue ram: Black ghost knifefish can eat German blue rams: they're small enough to fit in its mouth once it's grown.
  • Glowlight tetra: Black ghost knifefish can eat glowlight tetras: they're small enough to fit in its mouth once it's grown.
  • Harlequin rasbora: Black ghost knifefish can eat harlequin rasboras: they're small enough to fit in its mouth once it's grown.
  • Hillstream loach: Black ghost knifefish can eat hillstream loaches: they're small enough to fit in its mouth once it's grown.
  • Honey gourami: Black ghost knifefish can eat honey gouramis: they're small enough to fit in its mouth once it's grown.
  • Jack Dempsey: Jack Dempsey is aggressive and will bully or injure peaceful black ghost knifefish.
  • Julii corydoras: Black ghost knifefish can eat julii corydoras: they're small enough to fit in its mouth once it's grown.
  • Otocinclus: Black ghost knifefish can eat otocinclus: they're small enough to fit in its mouth once it's grown.
  • Pea puffer: Black ghost knifefish can eat pea puffers: they're small enough to fit in its mouth once it's grown. Pea puffer is aggressive and will bully or injure peaceful black ghost knifefish. Pea puffer is best kept in a species-only tank.
  • Peacock cichlid: Peacock cichlid is a Lake Malawi cichlid. It needs a Lake Malawi tank: hard, alkaline water (pH 7.5–8.5), plenty of rockwork and other cichlids from the same lake. Black ghost knifefish don't belong in that setup.
  • Peppered corydoras: Black ghost knifefish can eat peppered corydoras: they're small enough to fit in its mouth once it's grown.
  • Platy: Black ghost knifefish can eat platies: they're small enough to fit in its mouth once it's grown.
  • Pygmy corydoras: Black ghost knifefish can eat pygmy corydoras: they're small enough to fit in its mouth once it's grown.
  • Red zebra cichlid: Red zebra cichlid is aggressive and will bully or injure peaceful black ghost knifefish. Red zebra cichlid is a Lake Malawi cichlid. It needs a Lake Malawi tank: hard, alkaline water (pH 7.5–8.5), plenty of rockwork and other cichlids from the same lake. Black ghost knifefish don't belong in that setup.
  • Rummy-nose tetra: Black ghost knifefish can eat rummy-nose tetras: they're small enough to fit in its mouth once it's grown.
  • Sterbai corydoras: Black ghost knifefish can eat sterbai corydoras: they're small enough to fit in its mouth once it's grown.
  • White cloud mountain minnow: They need different temperatures: Black ghost knifefish 24–28°C (75–82°F), white cloud mountain minnow 16–22°C (61–72°F). Black ghost knifefish can eat white cloud mountain minnows: they're small enough to fit in its mouth once it's grown.
  • X-ray tetra: Black ghost knifefish can eat x-ray tetras: they're small enough to fit in its mouth once it's grown.
  • Agassiz's dwarf cichlid: Black ghost knifefish can eat Agassiz's dwarf cichlids: they're small enough to fit in its mouth once it's grown.
  • Black neon tetra: Black ghost knifefish can eat black neon tetras: they're small enough to fit in its mouth once it's grown.
  • Black phantom tetra: Black ghost knifefish can eat black phantom tetras: they're small enough to fit in its mouth once it's grown.
  • Bleeding heart tetra: Black ghost knifefish can eat bleeding heart tetras: they're small enough to fit in its mouth once it's grown.
  • Bloodfin tetra: Black ghost knifefish can eat bloodfin tetras: they're small enough to fit in its mouth once it's grown.
  • Buenos Aires tetra: Black ghost knifefish can eat buenos Aires tetras: they're small enough to fit in its mouth once it's grown.
  • Clown killifish: Black ghost knifefish can eat clown killifish: they're small enough to fit in its mouth once it's grown.
  • Crystal red shrimp: Black ghost knifefish eats small shrimp like crystal red shrimp.
  • Demasoni cichlid: Demasoni cichlid is aggressive and will bully or injure peaceful black ghost knifefish. Demasoni cichlid is a Lake Malawi cichlid. It needs a Lake Malawi tank: hard, alkaline water (pH 7.5–8.5), plenty of rockwork and other cichlids from the same lake. Black ghost knifefish don't belong in that setup.
  • Diamond tetra: Black ghost knifefish can eat diamond tetras: they're small enough to fit in its mouth once it's grown.
  • Dwarf chain loach: Black ghost knifefish can eat dwarf chain loaches: they're small enough to fit in its mouth once it's grown.
  • Emperor tetra: Black ghost knifefish can eat emperor tetras: they're small enough to fit in its mouth once it's grown.
  • Endler's livebearer: Black ghost knifefish can eat Endler's livebearers: they're small enough to fit in its mouth once it's grown.
  • Forktail blue-eye: Black ghost knifefish can eat forktail blue-eyes: they're small enough to fit in its mouth once it's grown.
  • Frontosa: Frontosa is a Lake Tanganyika cichlid. It needs a Lake Tanganyika tank: hard, alkaline water (pH 8–9), plenty of rockwork and other cichlids from the same lake. Black ghost knifefish don't belong in that setup.
  • Gardneri killifish: Black ghost knifefish can eat gardneri killifish: they're small enough to fit in its mouth once it's grown.
  • Glass catfish: Black ghost knifefish can eat glass catfish: they're small enough to fit in its mouth once it's grown.
  • Gold barb: Black ghost knifefish can eat gold barbs: they're small enough to fit in its mouth once it's grown.
  • Green terror: Green terror is aggressive and will bully or injure peaceful black ghost knifefish.
  • Head and tail light tetra: Black ghost knifefish can eat head and tail light tetras: they're small enough to fit in its mouth once it's grown.
  • Jewel cichlid: Jewel cichlid is aggressive and will bully or injure peaceful black ghost knifefish.
  • Kubotai rasbora: Black ghost knifefish can eat kubotai rasboras: they're small enough to fit in its mouth once it's grown.
  • Lambchop rasbora: Black ghost knifefish can eat lambchop rasboras: they're small enough to fit in its mouth once it's grown.
  • Lemon tetra: Black ghost knifefish can eat lemon tetras: they're small enough to fit in its mouth once it's grown.
  • Marbled hatchetfish: Black ghost knifefish can eat marbled hatchetfish: they're small enough to fit in its mouth once it's grown.
  • Odessa barb: Black ghost knifefish can eat odessa barbs: they're small enough to fit in its mouth once it's grown.
  • Peacock gudgeon: Black ghost knifefish can eat peacock gudgeons: they're small enough to fit in its mouth once it's grown.
  • Penguin tetra: Black ghost knifefish can eat penguin tetras: they're small enough to fit in its mouth once it's grown.
  • Rosy loach: Black ghost knifefish can eat rosy loaches: they're small enough to fit in its mouth once it's grown.
  • Rosy tetra: Black ghost knifefish can eat rosy tetras: they're small enough to fit in its mouth once it's grown.
  • Scarlet badis: Black ghost knifefish can eat scarlet badis: they're small enough to fit in its mouth once it's grown.
  • Serpae tetra: Black ghost knifefish can eat serpae tetras: they're small enough to fit in its mouth once it's grown.
  • Shell dweller cichlid: Black ghost knifefish can eat shell dweller cichlids: they're small enough to fit in its mouth once it's grown. Shell dweller cichlid is a Lake Tanganyika cichlid. It needs a Lake Tanganyika tank: hard, alkaline water (pH 7.5–9), plenty of rockwork and other cichlids from the same lake. Black ghost knifefish don't belong in that setup.
  • Sparkling gourami: Black ghost knifefish can eat sparkling gouramis: they're small enough to fit in its mouth once it's grown.
  • Threadfin rainbowfish: Black ghost knifefish can eat threadfin rainbowfish: they're small enough to fit in its mouth once it's grown.
  • Black ruby barb: Black ghost knifefish can eat black ruby barbs: they're small enough to fit in its mouth once it's grown.
  • Checkerboard barb: Black ghost knifefish can eat checkerboard barbs: they're small enough to fit in its mouth once it's grown.
  • Dwarf rasbora: Black ghost knifefish can eat dwarf rasboras: they're small enough to fit in its mouth once it's grown.
  • Flame tetra: Black ghost knifefish can eat flame tetras: they're small enough to fit in its mouth once it's grown.
  • Glowlight danio: Black ghost knifefish can eat glowlight danios: they're small enough to fit in its mouth once it's grown.
  • Green neon tetra: Black ghost knifefish can eat green neon tetras: they're small enough to fit in its mouth once it's grown.
  • Least killifish: Black ghost knifefish can eat least killifish: they're small enough to fit in its mouth once it's grown.
  • Pearl danio: Black ghost knifefish can eat pearl danios: they're small enough to fit in its mouth once it's grown.
  • Silvertip tetra: Black ghost knifefish can eat silvertip tetras: they're small enough to fit in its mouth once it's grown.
  • Variatus platy: Black ghost knifefish can eat variatus platies: they're small enough to fit in its mouth once it's grown.

Frequently asked questions

What fish can live with black ghost knifefish?

Good tank mates for black ghost knifefish include nerite snail, angelfish, oscar, assassin snail, ramshorn snail and malaysian trumpet snail. They need similar water and won't fight with or eat black ghost knifefish.

Can black ghost knifefish live with angelfish?

Yes. They share similar water needs (24–28°C (75–82°F)) and peaceful temperaments.

Can black ghost knifefish live with bettas?

No. Black ghost knifefish can eat bettas: they're small enough to fit in its mouth once it's grown.

Can black ghost knifefish live with bristlenose plecos?

Sometimes, with care. Bristlenose pleco defends its patch of the bottom and may chase black ghost knifefish, which use the same area.

Can black ghost knifefish live with bronze corydoras?

No. Black ghost knifefish can eat bronze corydoras: they're small enough to fit in its mouth once it's grown.

How we decide: we compare each pair's comfortable temperature, pH and hardness ranges, adult sizes, mouth size (who can eat whom), fin nipping, aggression and territory. Read the full method. Data last reviewed 2026-10-13.