Well, cichlids are a type of fish. Cichlidae, to be more specific. They are the 'family' classification, that are further spilt down into genus and then species.
Cichlids are found all over the world. Almost every continent has cichlids. The most common ones are from Africa (both Rift Lake and riverine cichlids, requireing different water chemistry), South American, and Central America.
Here is a website on AFRICAN cichlids from a Rift Lake, Lake Malawi. Just one of the many biotopes that cichlids inhabit.
http://www.malawimayhem.com
You really cant just sum up what cichlids need, since there are so many different kinds that need different things. But if you were interested in african rift-lake cichlids, then the most common ones are from malawi and you should check out that link. They have species profiles on many many malawies. You can also do a google search to pull up many other sites.
Here's a good article on a first-time setup for Malawi Cichlids
http://www.malawimayhem.com/articles_setup_01.shtml
http://www.cichlid-forum.com Is a great site that deals will all types of cichlids, not just malawi. There you can browse pictures of ones from all over the world.
Cichlids, hands down, are one of the most intelligent types of fish. They are smart enough to recognize thier owner, and form lasting personalities. The way they interact with one another is very unique as well.
HTH
-Diana
