Originally Posted by
DJW
In the Amazon the fish have a choice, to be in the faster flow (avg 2.2 feet/second) or to be in the slower water at the edges or in eddies and slow tributaries.
In a glass cage there need to be places where the fish can be at rest, while providing enough flow for filtration and some circulation for oxygen transfer at the surface. Most tanks have filters that turn between 3 and 10 times the tank volume per hour, and the flow can be managed so that the fish are not stressed.