New Tank-Gravel

Question
Chris, I have a 20gal tank that I set up about 6wks. ago.  Are
2-2 1/2 inches of river stones too much?  I've read that the Otos cannot get to the debris that falls deeper between the stones, that it should be no deeper than 1/2 inch. Is this true?  I've removed about 2 lbs. so far.  Thanks, Janis

Answer
Hi Janis;

The deepest your gravel should be is about a half-inch to an inch really. Fish can't get under the first layer of rocks to forage unless the fish is a big guy like a cichlid or something. It's especially dangerous for small bottom-feeder fish and algae eaters such as otos. They can get their little heads stuck in between the rocks. I've seen it happen in tanks that have round marbles as decorations. Especially betta tanks. Bettas try to get food that falls between the rocks, get their heads stuck and they actually drown. Yikes.

The only exception to the shallow depth is if you have an undergravel filter. It is recommended to have 2 to 4 inches on top of the UG plates. Undergravel filters use the gravel as the place for beneficial bacteria to grow. The deeper the gravel, the more places that beneficial bacteria has to grow. Oxygenated water constantly flows through the gravel so the depth is not a problem.

At Your Service;
Chris Robbins