fish · Apteronotidae
Black ghost knifefish
Apteronotus albifrons
Wild range: Northern and central South America — Amazon and Orinoco basins, Guianas coastal rivers, and Paraguay–Paraná system; among the most widespread apteronotids (South America)
At a glance: Black ghost knifefish care
Compiled reference information. Review the care notes and original sources below.
What temperature is listed for Black ghost knifefish?
The compiled profile lists 23.0–28.0 °C for Black ghost knifefish (Apteronotus albifrons). Check the original sources below for context and differing recommendations.
What tank size is listed for Black ghost knifefish?
The profile lists a minimum tank volume of 100.0 US gallons (379.0 liters). Volume alone does not establish suitability; consider dimensions, group size and other inhabitants alongside the full care notes.
What pH is listed for Black ghost knifefish?
The compiled profile lists a pH of 6.5–7.8. Review the cited care sources alongside the other water parameters in this profile.
Natural habitat
Rapidly flowing freshwater creeks and rivers with sandy bottoms, driftwood, rocks, and dense cover; often turbid/murky with low light. Nocturnal weakly electric micro-predator that navigates and hunts via continuous electric organ discharges (FishBase, Wikipedia, Aquarium Co-Op, Fish Laboratory).
Where they are found
Catalog primary locked as Apteronotus albifrons (Linnaeus, 1766) per trade/inventory lock, ITIS TSN 163328 (taxonUsageRating: valid), FishBase, and Eschmeyer’s Catalog of Fishes (online, checked 2026-09-25) Current status: Valid as Apteronotus albifrons (Linnaeus 1766). Older combinations/synonyms recorded here and in aliases: Gymnotus albifrons Linnaeus 1766; Apteronotus passan Lacepède 1800 (unnecessary replacement name); Sternarchus lacepedii Castelnau 1855; Sternarchus maximilliani Castelnau 1855. No CoF/FishBase rename away from Apteronotus — primary retained per Scott naming rule 2026-09-24 without taxonomy deferral. Distinct from Asian Notopterus / African Xenomystus ‘ghost/knifefish’ trade names (different orders). IUCN Least Concern (assessed 2020/2022).
Aquarium care
Large South American oddball kept for ribbon-fin swimming and weak electrolocation — not a beginner nano fish. Plan at least a 100 US gallon (~379 L) long-footprint tank for one adult (Fish Laboratory 100 gal floor; World of Aquariums 125; Aquarium Co-Op says 55 gal may work year one and 75 interim, but recommends 120–180 gal for long-term adults — locked 100 gal minimum with longer tanks strongly preferred). Soft-to-medium water ~23–28°C, pH ~6.5–7.8, GH ~5–15 (FishBase 23–28°C / 6.0–8.0 / dH 5–19; Fish Laboratory 23–28 / 6.0–8.0 / 5–19 dGH; Aquarium Co-Op 24–28 / 6.8–7.8 / ≥5° GH; World of Aquariums 73–82°F≈23–28 / 6–7.5 / 3–12 — locked overlap 23–28°C, 6.5–7.8, 5–15). Low lighting, smooth sand/gravel (scaleless — avoid sharp décor), PVC tubes/caves/driftwood, and hardy low-light plants. Moderate flow and excellent filtration/water quality. Intermediate difficulty; copper medications are hazardous to this scaleless species.
Feeding
Carnivorous micro-predator of insect larvae, small crustaceans, and small fish in nature (FishBase, Wikipedia, Fish Laboratory). In aquaria: frozen/live bloodworms, brine shrimp, tubifex, prawns/mysis, and meaty pellets that fit the mouth; flakes alone are usually inadequate (Aquarium Co-Op, Fish Laboratory). Nocturnal — feed after lights-out or train to surface/hand-feed floating foods. Will eat neon-sized tankmates once large.
Compatibility
Generally peaceful toward similar-sized non-electric tankmates but predatory on nano fish and territorial toward other weakly electric fishes (other knifefish, elephantnoses, etc.) — Aquarium Co-Op advises against housing two BGKs in typical tanks. Suitable companions when adult: Geophagus, peaceful larger catfish, angelfish, silver dollars, robust peaceful cichlids ≥~15 cm (Aquarium Co-Op, Fish Laboratory). Not community-safe with neons/small tetras once mature. Species/oddball showpiece tank preferred.
Breeding
Difficult egg-layers; commercially farmed but hobby spawns are uncommon (Fish Laboratory, World of Aquariums, Wikipedia). Fractional spawners hide sticky eggs in crevices at night; hatch in days; little/no parental care; adults may eat eggs. Inducing spawn often involves large volume, conductivity/water-change cues, and compatible pairs; literature cites very large tanks/ponds for breeding groups. Sexual dimorphism subtle (body shape / EOD frequency).
Sources
Compiled from multiple independent care sheets — not copied from a single site.