Aquarium Gravel

In practice it is entirely possible to keep fishes indefinitely in a bare aquarium. They do not require gravel, plants, rocks, or ornaments. But how many people would keep such an aquarium in a living room? An aquarium to be properly enjoyed should be a thing of beauty, a miniature underwater garden.

Gravel is used primarily as a rooting medium for the plants. A depth of 1 to 2 inches is usually sufficient. The greater the depth of the gravel, the greater the likelihood the water in the aquarium will be polluted. To avoid pollution, many aquarists put their plants in small pots which are set on the bare floor of the aquarium, even though this does not look as attractive as other plantings. When using this method, it is best to keep a thin layer of gravel, about 1- inch deep, over the aquarium bottom. This will “hold” settlings. It should be siphoned up and replaced with fresh gravel when cleaning the aquarium.

Crushed rock, preferably containing no lime, is best. To test for lime, drip some hydrochloric acid on the grave if it fizzes, lime is present. Medium grade #2 or #3 gravel is most satisfactory. The size of the granules should be about twice the size of a pin head.

Plants do not grow so well in fine gravel as in coarse; but if the gravel is too coarse, bits of food will drop into the spaces between the particles, where the fishes will not be able to get at them. So gravel size is important. Note: never use sand. Sand is so fine that there is very little circulation throughout. Putrefaction takes place very readily under such circumstances.

Do not try to wash too much at once: 3 to 6 pounds at a washing is enough. Place this amount in a large pot or bucket. While running faucet water on it, stir the gravel well; then pour off the dirty water. Repeat until no more dirt can be stirred up. Using a sieve or colander for washing gravel is often unsatisfactory. There is then no way of telling whether all the dirt has been washed out.

Some aquarists report good results from the use of layer of well-washed river mud below the gravel. The dangers of such a procedure far outweigh the possible benefits. Should organic matter be introduced in the mud, its decomposition will pollute the aquarium. The pH of the aquarium is frequently disturbed by the use of mud. Uprooting a plant by the aquarist or natural rooting by a Catfish can disturb the mud and result in a cloudy, messy tank.