Ok. theres about 0 usefull information in this thread... It seems like a lot of computer geeks are clueless about fish.
If your not gonna read the below, please go to another forum for advice on fish.
For freshwater I would recommend
www.aquariacentral.com to the beginner
For saltwater, definately go to
www.reefcentral.com
Since I had up to about 5 tanks in the past few years, but now concentrate more on my reef tank heres some advice.
Ich can stay in the substrate of your tank and wait for new fish to arrive. If you add new fish in now, you may have the same problems.
Hopefully since you did mention the nitrogen cycle you seem like you already know what it is. Hopefully you've done all your water tests and know that your tank is safe.
For the person who said chlorine dissolives in 24 hrs, yes its true, but most munincipal tap water has chlormine added to it which will not dissipate, you need to add water conditioner still.
African cichlids aren't particularly "aggressive" in that they dont kill for food the way South Americans do. At least the common ones in fish stores. THey are territorial. If your fish are killing each other its because you have inadequate space, and/or you dont have suitable rock structure for them. I have about 25 African cichlids and they get a long great. The cichlids you hear about drawing blood are usualy Oscars which are also great fish. This are usualy 10"+ specimens however and I very much doubt you have a 10"+ African...
Finaly, higher temp can help treat ich as the life cycle of the bacteria dies faster etc etc... Normaly though your fish only get ich because they are stressed not healthy. Same as humans. Its usualy in the water, but its not until something else makes them not healthy that it gets to infect and spread.