Q & A

Here you will find answers to questions submitted via the "Ask Aquaworld" web form by viewers of the Aquaworld Aquarium web site. If you have a question you would like us to answer, go to the Ask Aquaworld web form.

Black Ghost Knifefish

Dear Aquaworld,

We have a black knife fish. Do they eat other fish? We keep noticing a depletion of our guppies! Especially babies. He is about 5 inches long.

Julie
Winter Garden, Florida, USA

Dear Julie,

A 4 inch (10 cm) juvenile Black Ghost Knifefish (Apteronotus albifrons).

If the fish in question is what is commonly called the Black Ghost Knifefish (Apteronotus albifrons), yes they will eat small fish including guppies. This fish is primarily nocturnal and will eat fish while they sleep. Also these fish can get quite large, over 18 inches (45 cm), and it is recommended that they be housed in an aquarium that is 120 gallons (456 l) or larger.

Good Luck!

Tony Griffitts