Originally Posted by 55Range
Ok By warm you mean Discus and loaches I guess. Well its a 5 feet tank. With plants. caves, hiding places, and have had many of those fish some since 4 years and some as little as a month.
What are you suggesting ?
Yes, the discus are warm water, 82F and above. Weather loach is temperate, mid-70's is the highest it should be kept. The other fish listed can manage with normal community temperatures around 77-79F, some will manage at the higher discus range, some at the lower. In general, it is usually best to maintain fish at the lower to mid-range of their preference since this will allow them to metabolise more easily with less effort. The higher the temp, the more the fish must work.
The knifefish is not a community fish, and it will require much larger quarters. At nearly 2 feet and being stiff-bodied, it cannot turn around in a tank that is not at least as wide as its length (2 feet at maturity). The dim lighting it needs (being nocturnal) will suite discus and loaches, though not your plants. You mention ghosts in the plural; this fish is electrogenetic, and thus should be kept one fish per tank to avoid stress.
I am an advocate of only mixing truly suitable fish species in an aquarium, regardless of the size. There is sufficient evidence nowdays to show that this is the best way to reduce stress on the fish, and that means healthier fish. Nothing is cast in stone, but at the same time the inherent traits of each species is a given by nature, and the effects of these things are not always easily seen by the aquarist. Discretion is the better part of valour, and similarly avoiding possible (even if not probable) problems is the safer and wiser course. We have fish profiles, second tab from the left in the blue bar across the top of the page, and each profile contains info on numbers for shoaling fish (of which many here are), compatibility, etc.