There is a misconception that riverine fish need to live in whirlpool-like conditions to simulate their natural environment. This is an incorrect assumption and recreating that environment can lead to some unhappy cichlids. Their body shapes are designed to keep them out of the fast flowing water. I would like to share a setup that I have used for quite some time and has lead to success in raising and breeding rheophilic cichlids.
The key to a successful setup is placement of the filtration and aquascaping design. While rapidly moving current is not a requirement, the need to have well oxygenated water certainly is. I accomplish this goal by using a filter with a higher flow rate than required for the tank size. I prefer Aqua Clear® brands because of the large volume of water they move. This may seem contradictory of my earlier statement about excessive water flow in the tank. To offset the increase in flow and keep substrate and plants from blowing all over the aquarium, I place a large rock under the outflow. This functions as a diffuser and spreads the surge throughout the tank without consuming the environment. Let's take a look at the various sections of the tank.
Zone 1: Here you can see the flow of the filter directly over the rock. There are several benefits to having an object at this location. Décor placed here hide the filter's intake tube and creates areas of seclusion for sub-dominant fish and fry.