Freshwater Fish
Black Ghost Knifefish.
A velvety-black, ribbon-bodied fish that glides backward and forward on a single rippling fin and navigates by a weak electric field. It grows large — plan on a 100-gallon-plus tank — and wants caves, dim light, and peaceful tankmates it can't swallow.
We keep this species at our Erie store. Come and see it in the tanks, or call (814) 456-9445 and ask what we have in right now.
Sea Cave keeps this species. You will find these in the tanks at 660 East 14th Street in Erie. We never ship live animals.
- Condition
- new
- Fulfillment
- Local pickup — Erie, PA
We never ship fish, coral, or invertebrates — every animal here is one you meet in person. Each one is acclimated and health-checked in-house before it goes out into the display tanks. This is a species we keep, and what is swimming on any given day changes with the deliveries, so please call (814) 456-9445 before you drive in.
Care at a glance
What to know before you take one home.
- Care level
- Advanced
- Temperament
- Semi aggressive
- Community
- Semi community
- Adult size
- 20"
- Min tank size
- 55–150 gal by age
- Diet
- Carnivore
- Scientific name
- Apteronotus albifrons
Grows into its tank
Juvenile (~1 yr)55 galAdult150 galGood tank mates
Semi-aggressive and a nighttime hunter, the black ghost knifefish needs calm tankmates that are too big to fit in its mouth but not so boisterous that they outcompete it for food. Think medium peaceful fish like larger gouramis, bigger tetras such as Congo tetras, angelfish, or peaceful South American cichlids. Avoid tiny fish like neons and ember tetras (they get eaten), fin-nippers, and other aggressive or territorial knifefish. This is not a fish for a small peaceful nano community.
Good to know
The black ghost knifefish navigates and finds food using a weak electric field it generates, which lets it hunt in the dark.
What is in the tanks and each animal's temperament vary — call (814) 456-9445 for pairing advice.
Good tankmates
Plays well with.
Species we’d keep in the same tank, with why each pairing works. What is in the tanks and each animal’s temperament vary — call (814) 456-9445 for advice on pairing.
New to stocking a tank? Read our guide on which fish live together.
Assorted Angelfish
Widely documented compatible pairing — the Vancouver Aquarium keeps them together long-term. Angelfish are diurnal while the BGK is nocturnal, so activity windows barely overlap, and angelfish pose no fin-nipping or predation risk to the knifefish.
Red Spot Silver Dollar
Fast, peaceful, South American schooling fish reaching 6–8 inches — too large to be eaten and too quick and non-aggressive to threaten the knifefish. Multiple aquarist sources confirm this pairing.
Electric Blue Acara
Calm, semi-peaceful cichlid that reaches 6–7 inches and is not known to harass or nip at the scaleless knifefish. Confirmed compatible by multiple aquarium care guides, with no documented pattern of bullying the BGK.
- G
Geophagus Eartheater Cichlid
Peaceful, similarly sized South American cichlid that shares the same warm, soft, slightly acidic water parameters as the BGK and is not known to bully or compete aggressively with it.
Visit the store
660 East 14th Street,
Erie, PA.
Mon–Fri 12–6 · Sat 11–4 · Sun closed. Call ahead on livestock — what's on the floor rotates.