Originally Posted by saulat
Had a lot of trouble logging back in. In regards to the rainbow sharks they did great in my 75 gallon before I downgraded to the 48 gallon. They have barely left the corner of this tank. I think this is because I agreed to take these small cichlids when I bought the tank, mainly because the guy had nowhere else to put them. I was hoping my eel would have eaten them by now. I fished them out today and donated them to the store. Already, my rainbow sharks are moving around the tank and I see one has a large piece of his dorsal fin missing. The cichlids also picked one of my corys to death as well.
The snails I always thought would lead to a massive infestation, I guess there isn't too much for me to worry about. I noticed that at the store the only tanks without snails were the clown loaches and the angelicus botia which I considered getting however, my eel would probably eat them. I am thinking of getting him his own tank as he lunged at a rasbora het today and I would really like to avoid him eating any fish that I like lol.
You don't mention which cichlid(s), some will tear into other fish they don't particularly "like".
Two rainbows in less than a 4-foot tank is not advised; now that they are somewhat more relaxed (from what you've said), they may begin to act more naturally toward each other and that could be a problem. Have a look at the profile of the Rainbow Shark and you'll see what I'm getting at.
I would definitely recommend moving the tiretrack eel. Having a predatory fish in the tank is going to stress out the other fish, even if the eel does not physically "attack" them. He is sending out signals via behaviours, pheromones, etc., and other fish can pick up on these. In nature, the other fish would flee and avoid the predator if possible; in the aquarium they are confined and can't, so it is highly stressful. This weakens the immune system (just as in humans) and they become mores susceptible to health problems, parasites, etc. You really cannot have aggressive fish in with peaceful fish like rasbora, most characins, gourami, angels, and so forth.
I have once or twice acquired small fish that I thought would do fine in my 115g tank, only to have them settled down in a few days and become terrors to the other characins. Just bey being there, and "chasing". The other fish remained among the plants, hidden, and refused to come out even to feed. I got rid of the offenders, and everything settled down. Compatibility is not always easy to assess, but taking to heart the info in our profiles or similar sites about the expected behaviours of fish before deciding to get them is wise.