How to Care for a Black Ghost Knifefish

Co-authored by Craig Morton

Last Updated: August 3, 2024

From the Amazon river comes a beautiful species of nocturnal fish. Growing up to 20 inches (49 cm), the black ghost knifefish has a spot in the heart of every fish keeper.

Part 1

Part 1 of 2:

Providing a Good Habitat

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1
Get a large enough tank. In the aquarium world, the knifefish is a large fish that needs a large tank. It is suggested to use a minimum of a 125-gallon tank for a single knifefish. You should do 30-50% water changes each week.
- The knifefish will spend most of its time in the bottom of the tank.
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2
Keep that water warm. The temperature your tank should be between 73 and 83 degrees Fahrenheit (22.8-27.8 degrees Celsius). You will need a tank thermometer to tell the water temperature inside the tank. A tank heater may be needed (depending on where you live) to get the water to an acceptable temperature range.
- If the water temperature is under 73 degrees Fahrenheit (22.8 Celsius), The fish could become sluggish or to lose its appetite.
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To find the pH of the tank you will need pH strips.
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The substrate should be either sand or gravel to replicate the knifefish's natural environment. The substrate needs to be fairly soft to prevent harm to your fish.
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5
Provide many hiding places for your fish. Whether your decorations are plants, rocks, or wood, you should have many decorations to help your knifefish feel secure.
- Some owners have a clear tube in the tank so the owner can see the fish but the fish still feels secure.
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Choose a tank mate that is about the same size as your knifefish. These fish are peaceful to other fish that are the same size as them but, can become aggressive with other ghost knifefish. Make sure your tank mate isn't too small so it isn't mistaken for a meal.
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Coming from the Amazon river, knifefish are used to moderate to strong water flows. A good water flow gives your fish mush needed exercise to keep it healthy.
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Knifefish are nocturnal and used to hunting in the dark. During the day, use none or very little light. At night, use some low-level lighting so you can see the fish when its active.
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Make sure your filter can any and all waste and impurities. Knifefish are very sensitive to things in the water like ammonia, nitrites, and nitrates.

Part 2

Part 2 of 2:

Feeding

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1
Feed live food. In the wild, the knifefish eats insect larva, insects, worms and small fish so replicate this diet in your tank. To replicate the diet you can use foods such as:
- Brine shrimp
- Bloodworms
- Blackworms
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Once acclimated, your knifefish should come out for feeding. If you see that your fish is shy, feed it multiple times a day to help it get used to coming out. These fish are one of the few fish that you can hand feed. Hand-feeding requires a good bond between the fish and the owner so don't expect to be able to right away. When hand feeding, make sure that you don't have any soaps or perfumes on your hand because these are toxic to fish.
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Sickness can be transferred from anything from plants to feeder food. Make sure to properly quarantine anything that you add to your tank and to only buy your food from reputable sources that you trust. Knifefish are prone to skin flukes, parasitic infestations (protozoa, ichthyobodo, worms), bacterial infections, and bacterial diseases.

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Can I feed artemia to black ghost knife?

Community Answer

Yes. Feeding brine shrimp to a black ghost knife fish is perfectly okay. You can also try sinking carnivore pellets. You can feed blood worms, tubifex, brine shrimp, or any type of meaty foods, since black ghost knife fish are strictly carnivores.

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A UV sterilizer can prevent many diseases.

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Warnings

Never use copper in a ghost knifefish tank.

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Don't have anything rough in your aquarium. Knifefish don't have scales and could get hurt on rough items.

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Expert Interview

Thanks for reading our article! If you’d like to learn more about fish and aquarium care, check out our in-depth interview with Craig Morton .

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How to Care for a Black Ghost Knifefish

Steps

Providing a Good Habitat

Feeding

Community Q&A

Tips

Warnings

Expert Interview

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