In an effort to run my system with fish that can be sold in the pet fish trade, I've been experimenting with certain cichlids in my systems. Namely Midas and Mayan cichlids as well as spotted tilapia. Not surprisingly, they have proven to be less than ideal in my systems due to their aggressiveness and territorial nature. As it is now, they are all in the same 400 gallon pond and the smaller/weaker ones have been weeded out by the more aggressive ones. This has lead to a low number of larger fish and ultimately malnutrition to the plants. There has been some successful breeding, however, by the spotted tilapia. I have a bunch of their fingerlings in the pond, but its not a species that has much value in the pet trade.
However, if used differently, i feel the cichlids may be able to work. If the parents are kept in breeding tanks and the main pond is used as grow out tank for the offspring for the young maybe there would be enough nutrients to feed the plants. In this scenario the breeding tanks and the grow out tanks would be connected to the system, just in separate containers.
So long as the offspring are able to be removed from the systems and sold or fed off before they became too aggressive towards one another, I think this is feasible.
I know many tilapia based systems are run in a similar manner, but I dont think they are usually done with the intention of selling off the young. This is also more tricky due to the mentioned aggressive nature of most other cichid species. However, the possibility of income from the sale of the fish might make it worth while.
Excluding koi,which are not ideally suited to my neck of the woods, has anyone tried anything like this?
Your right, if your going to breed ornamental cichids you need to get several tanks, one for each breeding pair. These fish tend to get vicious when defending their breeding ground. You would also need multiple tanks for raising the fry to marketable size as you would need to keep separate batches separate.Even within one spawning you may find that the runts get cannibalized. I would suggest you tackle one species first, as I would expect one prolific pair needing several large tanks for growing all the fry to marketable size. Also, you may want to consider your choice of species. The ones you mention have a limited market due to their aggressive nature. If you start producing large quantities of fish you'll need a market for them as well.