I think most of the concern over tank size is just because we see time and time again that people take precautions and plan to upgrade and completely underestimate how quick these fish can grow.
That said... I was perfectly happy that you understood how fast they can grow and have considered the future already... though personally I don't see the point in getting a fish that I would get attached to and then have to give away.... but each to their own. I think we have to accept here that we can give our advice and accept the results. People don't have to agree with our advise and it isn't anything personal or anything we can do about. People are allowed their own opinions and some people sadly have to learn the hard way.
I have personally found that really young knife fish that aren't settled only eat when they have a lot of hiding places (at least 3-4 cafes or gaps between wood and rocks etc) and at first, only when lights are out or dim. I also find when starting out that they only really show interest in Bloodworm. They seem more willing to move onto other foods once they have a good appetite for bloodworms going.
I personally don't think training a fish to eat live food is a good idea, it makes them much harder to rehome or house with other fish when you are encouraging them to hunt other fish.
If you need to make sure food is getting to him, give him a hidey hole where you'll he'll be and using a short length of hollow pipe, put it in tank down to his hidey place and drop some defrosted bloodworm down the tube. Target feeding... you can gradually train him to come to the surface to feed from tube so you can see him and check him over each day...
My BGK is about a foot long now maybe more, i've had him for about 2 or more years. He eats flakes, shrimp pellets, live guppies, live ghost shrimp, frozen tilpai, frozen whitning, and fresh caught fish from the gulf he loves to eat the cut up fish fillets. I have him in a 75 gallon aquarium and he comes out all the time. Love him but I dont really have any suggestions i just drop food in the tank and he eats it, hes with bichirs so no competition for food.
Two days ago I impulsively bought a black ghost knifefish. I am having some trouble feeding him! I could really use some situation-specific advice as well as general advice going forward.
I currently (and very temporarily) have him housed in a small tank with a bumblebee goby, catfish (not sure of type), and 3 apple snails. 2 of the apples are small, the other is gigantic. Yes, I'm aware that knifefish get large and that he would eventually eat the goby... I'm getting a new, larger tank this week that should be ready for him before he grows very much. When he outgrows that, I have somebody to give him to. So no critique on that please!
Per my LFS I tried to feed him frozen krill. He seemed to have trouble finding it, but appeared to be searching for food. The apple snails quickly found and devoured the krill. Today, I realized he was friendly with my hand and let me "pet" him, so I tried to hand feed him and he went up to the krill but seemed disinterested, even after it was less frozen and was breaking apart.
What, in general, are my options for feeding him when he is this size? (~2.5in) How much should I feed him? (I've read/heard differing things).
Given that I have apple snails who are very quick and will eat literally anything left sitting around, and if I give him blackworms they will be hidden in sand or eaten by goby before he finds them, what can I do to make sure he eats?
I appreciate any help I can get! I want to figure out how to care for this buddy!