Biggest Black Ghost Knife

[EntoStentor]

The guy is doing the same thing as the people who make 5 foot rattlesnakes into titanoboa. He's holding it up way in front of the camera. Still a good catch.

 

[Josh's Fish]

So are you saying that they become less and less sensitive to light as they grow? Wow. I'd love to see mine more.
Here is a photo of him (I don't have a lot of these photos)View attachment 1363258

I wouldn't say they're sensitive to light, nor become less sensitive; rather the Chromatophore cells in the body which detect light just like their eyes, are adjusted to low levels of light. Just with any fish, if you turn on a light, it's suddenly daytime, and can be a shock for them. Black Ghost Knifefish at any size will happily come out during the day; some videos on YouTube of them resting in direct sunlight. They only have nocturnal tendencies, as hunting fish with poor night vision when the prey is less active at night is how they survive in the wild. Daytime is fine for them, I'd even encourage feeding during the day, and getting a transparent "ghost" tube for them to hide in. Feeding during the night, can encourage hunting behaviours, and don't underestimate what they can eat. I've lost a 11 inch armoured Ropefish to a 13" BGK.