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Hi Ya'll
The wife and I were considering the purchase of a new, larger tank. I would like a 55 but she wants bigger and ould like a black ghost knife if possible. What kind of setup would I need for that? tank size, plants substrate etc? What could I put in with it? How many could go in?
I would like as much info as I can before I decide.

A Black Ghost Knife Fish, Apteronotus albifrons, can grow to 20 inches. So your aquarium needs to be around 24 inches wide, possibly wider, and ideally at least 3 times longer, so you're potentially looking at a 6ft x 2ft x 2ft aquarium for long term housing. Ideally, even bigger than that. This means that if you want the fish to be happy, you're looking at 180 gallons minimum. So your wife is being wise wanting a larger tank.

Admittedly, in a tank that size, the Black Ghost Knife Fish need not be the only occupant. However, you must choose companions with care. Partly because the fish will eat small fishes during the night if presented unwisely with temptation to do so, and partly because the fish is a gnerator of electric fields for navigation purposes, so it might be wise to avoid certain other electric fishes such as Mormyrids in case there is a clash of fields.

The kind of companions the fish could share its home with include anything that's too large to eat, relatively peaceful, and relatively sedate in its movements. This would rule out fishes such as Tinfoil Barbs, which, while large enough (and in a 180 you would be able to house some - just) they're likely to be too active and intimidating for the Black Ghost Knife Fish. If you decide to run with the Black Ghost Knife Fish, go for the biggest tank you can lay your hands on right from the start, 180 gallons or up, and that way, you won't have to strip it down and replace it as the fish grows. Needless to say, with a tank that size, you will need to exercise care siting it vis-a-vis the structural strength of your floor joists, because once it's in place, it's going to be an immovable object weighing over half a ton, and when you factor in substrate and decor, you're looking at close on 900 Kg, possibly 1,000 Kg, which equals a metric ton. A base that spreads the load evenly across as many floor joists as possible is mandatory for a setup that size, unless you happen to be fortunate enough to place the aquarium on a reinforced concrete floor, in which case you have somewhat more leeway.

Decor that would be de rigeur for such a setup includes large bogwood root tangles that the Knife Fish can hide amongst, which will confer a feeling of security upon the fish, and possibly embolden it to the point that once it has settled in, it will start emerging into view at times that are relatively convenient for you, the aquarist. Be advised that for the first two weeks of acclimatisation, it WILL hide from view, and you'll have to tempt it out with 'lights out' feeding, which means that ideally, you should make the Knife Fish the first inmate of the aquarium, acclimatise it, then start planning any companions around it choosing with care as cited above. Floating plants to provide shade in strategic locations are definitely advisable (Pistia stratiotes being a good choice here in such a large tank) and other plants that would be advisable include Giant Vallisnera and large Amazon Swords.

One problem that will arise is filtration: the fish will place a fair amount of loading upon a filter system, but Black Ghost Knife fishes are native to relatively slow moving waters in the wild, and strong currents are likely to disagree with it. So you have to devise a filtration system that's efficient (with the requisite water turnover) but doesn't create a 'jacuzzi effect'. Arranging for the output of a large external canister filter to be sprayed across the water surface at the back of the aquarium using a spray bar is one possible solution here. Be sure that the inlet of such a filter is adequately guarded with a plastic cage to keep fishes from straying too close.

One thing you can be sure of is this - if you go with a 180 or larger right from the start, your Black Ghost Knife Fish will be a VERY happy fish. All too many of these are housed in aquaria that are totally inadequate for them, and a 180 gallon or larger setup will provide growing space for a good decade or so. If you can run to a 250, even better - you'll NEVER need to rehouse the fish if you start off with a 250, and it also gives you considerably more leeway with respect to companions in terms of numbers.

Among the bottom feeders that would live happily in there include Raphael Cats (too well armoured to be eaten even by a full grown adult, and in a 180+ they'll grow too big anyway) and some fairly interesting Loricariids. A 250 would even be big enough to let a Common Plec grow to a decent size, though if you're going to give your Black Ghost Knife Fish a 250, there's plenty of FAR more interesting and colourful Loricariids you could spend your money on that would make that big tank a show stopper. I'm sure Cup_of_Lifenoodles could suggest some excellent species for a 250 that would be compatible with the Knife Fish that would be catwalk stars compared to the dull brown Common Plec (a good specimen of Glyptopterichthys joselimianus comes to my mind, but I'd ask Cup if it would be compatible with the Knife Fish before shelling out on one). Likewise I'd do some research on likely compatibility issues before purchasing, say, a Leporacanthicus galaxias (which should do well in a 250!) or an L018 (this is a chunky Plec that hits 14 inches!).

Hope this epic post proves useful!


Panda Catfish fan and keeper/breeder since Christmas 2002

To get a quicker response. decide what size tank you want. If the wife saying go bigger than go bigger. Always keep the wife happy. who here wouldn't like there wife to say " 55 Gal tank No get a bigger one.

Anyway, a 75us gal tank you could still us a canister filter and any thing over that you will have to go with a wet/dry filter system. Another thing to take into consideration is time you have to spend on maintaining the tank. Water Changes things like that, do you want a community tank or species tank? As far a BGK, go to the profile section and see the info there it has been comprised of info from members here. Look at it see it you get good vibe form the fish. I know it likes caves and I have seen them in the canal down here in Miami,FL and they are quite large.

Djrichie
"Don't Panic"

Djrichie
"So Long, and Thanks For All The Fish" Douglas Adams

my largest ever BGK was about 25 inches and lived in a 75 gallon. 55 gallons is enough for adults but for small ones that would be ok to a point. like stated a larger tank is needed for adults.

i currently in my 55 gallon, have 7 BGKs. They are about 5 inches each. The way to set up a tank for them is alot of tubes and a hard set-up. I have little to no plants in that tank. Mostly driftwood, pipes. They seem to like powerheads. The can often be seen swimming by them.(something about electrical currents). One the bottom i use a course gravel. Sand would probably be better for them. Basically they all need something to hide by. So with all of the driftwood thats in the tank in combo with plenty og BGK pipes, and hamster pipes, they all have places to live.

edit: o and tankmates. Yea i dont understand why people would put them with tetras or community fishes. They are not in anyway community fishes. I currently keep them with convicts and other cichlids. When i had my largest, they shared a tank with a 24 inch clown knife, and a 26 inch irridencent shark(yes i know, the tank was very overstocked) larger cichlids would be better tankmates, but non aggressive.


Prehaps looking at green knives. OR glass knives sometimes called. They are more of a community fish only growing about 7 inches. looks like a BGK without the black. They are greenish tinted and kinda see threw. They would be fine in a community set-up in a 55 gallon.

i have a bgk(5-inches) in the my 29 gal until 60 gal that im getting next week cycles. when he gets bigger i will have to trade him in. my girl friend loves him and she told me it time to get a bigger tank. i love those words. the 60 is gonna be planted with allot of rocks

*click *flash *click "whered he go???"