When planning out your aquaruim’s water flow, keep the fish in mind when deciding on just how many gallons per hour you want running through your reef. Normally, we tell people to crank it up. Corals need environments that are free of detritus, and the best way to keep the fish waste and uneaten food out of the water is to remove it via various filtration methods. Water flow, of course, is paramount in helping to keep the detritus suspended in the water column, but not every fish can handle high flow systems. Take cardinalfish for example. They aren’t what you could consider strong swimmers. These fish generally hover in place, not moving more than a few inches at a time. Cardinalfish could thrive in a reef tank, but they might appreciate a lower flow rate so that they aren’t constantly being blown around and having to waste energy staying in position. Seahorses function similarly, and also don’t do well in high flow environments. Just be sure to keep these things in mind when picking out water pumps and aquarium livestock.