I have been keeping a single male GT as a center piece in a 75g for years with success. As long as the GT is the top fish and not picked on by more aggressive fish of comparable size, it works for me. I am not into bio type tank, and find mixing CA with rift lake cichlids perfect because their water quality requirements match. GT is SA from the Pacific rim requiring similar water chemistry as CA. Cichlids tend to be more aggressive towards its own or closely related species, so by being from different continents, American and African tolerate each other better. The mis match is behavior and size differences, which can be both the advantages and concern. My strategy is to keep single male of large Americans, single males of Haps, and breeding pairs or colony of smaller CA/SA and Tangs. With rock work, small Ca/SA and Tang will behave and breed naturally in the safety of rock caves. They may defend and attack larger tankmates but can't do harm because of their size, yet its fun to watch their natural behavior. Don't introduce female of large fish, GT or Haps as a breeding pair of GT will take up the whole tank, and breeding Haps are violent. Male Haps don't bond, only rape females violently, often after the females are done,and sometimes including male victims. My inclusion of male Haps is for the bright color, not for the behavior which stings. Egg laying Tangs are fine and they form interesting pair or colony bonding and it's fun to observe contrasting African behavior. But selection of Americans are limited by size and temperament. Some super large and aggressive CA such as RD, Faestae or Jaguar are out, but more mellow Viejas and Acara species work for me. All my show tanks are set up the same. I have breeding colony of Julie's in my 125, and breeding leulupi or daffodial in my 75, and occasionally I picked up fry from my breeding pairs of Crytoheros species, all in company with 9-14 inch single Americans.
