Black Ghost Knife (Apteronotus albifrons)

The black ghost knife was one of the first “odd ball” fish that really piqued my interest. I’d never seen a creature that moved like a black ghost knife before, and their morphology, back story, and use of electricity for sensory perception had me wanting one badly. Yet, since I’d never come across a fish like this before, I wasn’t really sure what to expect. Much research and planning later…


This was my first time really trying to get some photos of our little BGK, whom we named Ikki. Because they are mostly a dark, matte black, getting photos of a BGK is quite a challenge for my borrowed, not so great camera. Luckily, I took a good bunch of photos, and the ones here are those that seemed to come out best.

Here are some of Ikki hiding behind one of the filters in my 150 gallon. She’s got to be in such a big tank, because BGK can reach 15-18″ when fully grown. And yes, they will eat anything they can eat that fits in their eventually big mouth.

BGK have a short white stripe running from above their mouth along the top of their head, and two white bands on the tip of their tails. Ikki is ridiculously good at blending in among tall skinny plants like those often found in the areas of South America where most BGK are found. The rumor I’ve heard on various websites (that all seem to reference each other) is that indigenous peoples believed these fish to carry the soul of the dead. Maybe this is just an over repeated marketing ploy, but it’s a rather intriguing idea.

BGK are weakly electrical fish, meaning they can generate electricity, but it’s not enough to do much more than help them “see.” It acts as a radar of sorts, helping them locate food, avoid predators, and otherwise navigate. I love watching Ikki hunt for food, as she often hovers, moving forward and backward in a straight line via the long, contiguous bottom fin, while finding her target. Just watching Ikki explore the tank is a really cool experience.

Okay, and, lastly, here are some photos of Ikki being fed at the surface of the water. Black ghost knifefish can be easily trained to hand-feed, meaning you get to actually have your awesome fish eat gently from your hand. This was the initial step of this process – just getting Ikki comfortable feeding close to the surface while human hands are close/in the water nearby.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s