Only thing that concerns me is some of the tank mates. The barb is semi-aggresive and can get really nippy(may harass the BGK) the tetras/danio are schooling fish and do best in groups of at least 8. The algae eater unless true SAE gets very aggresive as it gets bigger(a problem for all mates). The pleco,unless dwarf, grows rapidly and may crowd the tank at full size. This link might help with you feeding ???'s

Here is a link that might be useful: BGK profile and reveiw

I've had other knife fish and they didn't eat flakes. Their favorite was live tubifex worms but they would take some frozen foods. Other fish usually don't bother knife fish, in fact the knife may eat some smaller fishes.

The barb checked him out but has left him alone. I know now that danios and tetras are school fish, but the danio, both tetras, and the barb tend to travel in a group. So far (and I've had the algae eater for 6 months-he's just shy length-wise of the knife), the algae eater doesn't mess with anyone now that I've got the betta on his own elsewhere. He occasionally sucks on the snail's shell, but that's about it. The pleco isn't a dwarf, but there's a pet-store nearby that buys the biggins to sell to people with massive tanks that need a big one, so if the pleco gets too big, he's got a home. But everyone seems to be getting along well.

I've just picked up some frozen brine shrimp to supplement the bloodworms, When he gets bigger, I'll start breeding guppies (since I've hearf that knife fish eat those...and keeping your own instead of buying questionable feeders is much better). I've also read that they like an occasional earthworm. Is it better to dig them up or to buy them at a bait shop (less likely involvement with chemicals, etc.)?

I would assume that the dug ones are fine. Careful of overfeeding with live foods. Too much leftovers may produce a worm growth of its own. Then again the knife would snack on those to. Breeding your own feeders is an excellent idea. Research breeding and set up a small fry tank with a sponge filter so the adult guppies dont eat them before they get big.

Just start a worm bed with some red wigglers (link below). Try to get him onto sinking carnivore pellets if he will take them. Go easy on the feeders only using them as suplements some ghost shrimp would probably work out well too. Young knife fish can be touchy make sure you raise him on a varied diet starting young and hopefully he will accept it as an adult.

I have two clown knives but they were fed feeders all their lives....they will only eat feeders now and take about 100 rosy reds a week. The varied diet is important so they don't get stuck in a rut and refuse other foods.

Adrea

Here is a link that might be useful: worm mans worm farm

I recently got a Black Ghost Knife and was curious if anyone knows if you can put more than 1 knife(either the same kind or a different one) in with him.

not sure but i doubt if 2 would get along. I've seen them in groups in store tanks and they usually have nipped tails.