Fish Tank Gravel

So let's talk gravel. It is not a glamorous topic, to be sure, but which kind you choose will effect how much tank cleaning you have to do, and how good your aquarium looks.

Most people never think about their fish tank gravel until the day they go to the fish store and buy a tank. Then they take a quick look at what kind of gravel the store offers, pick a color they like, and then buy about 5 bags of it. When they get home, they learn they did not buy enough gravel, so they go back for more a day or so later, after they've already set up the tank. This is not a terrible way to choose and get gravel, but there is room for improvement.

Large Gravel Pieces Make for Dirty Tanks

The rule with fish tank gravel is that the larger the pieces of gravel are, the dirtier your aquarium gets. So all those betta bowls out there with the large glass drops or "gemstones" for gravel -- all you guys are making your tanks dirtier than they need to be. The tanks get dirty because those large gaps between the gravel, or the glass drops, or the marbles you are using for gravel, trap fish waste and uneaten food. This waste tends to stay trapped down in the gravel, even when you do water changes. And even if you swish the gravel around when you do a water change, most of the waste falls back into the gaps between the gravel instead of getting washed away with the old water. Over time, you get a dirtier tank.

This does not mean you can't use marbles, or glass drops or "gemstones", or even river rocks for "gravel" in your tank, but it does mean that if you use these materials, you need to be a bit more active about doing water changes. Even the standard size gravel sold at most pet stores is a bit large for my taste -- I like the smaller pieces in natural colors, or "pebbles" for my tanks, or I use laterite if I have live plants.

Washing Gravel and Using Gravel from Anywhere Besides a Petstore

The other major thing to know about gravel is where you get it from. Any gravel from a pet store is OK, but you really, really ought to wash all new gravel in at least 3-4 thorough rinses before you put it in your fish tank. If you don't, you'll get gravel dust floating through the water, which will make it cloudy, and will make the tank seem dirty. So wash the gravel in a nice clean bucket in nice clean water until the water runs clear after you've churned up the gravel with your hand.

If you are considering using gravel that is not from a pet store, proceed with extreme caution. Any kind of soft rock, like limestone, or even sand, may have trace amounts of chemicals that can kill your fish. In the case of limestone, over time that may dissolve into the water and change the water chemistry in your tank. If you are doing lots of water changes you can compensate for this, but if you slack off on your tank maintenance you may have a problem.

If you are buying gravel for live plants, using materials like laterite, you will have to wash the gravel in as many as ten separate rinses if you want clear water when you fill the tank up. If you are using a base layer of clay on the bottom of a live plant tank, obviously you probably do not want to try to rinse clay.

Buying Gravel

If you want to get really cool-looking gravel, or gravel for planted tanks, you many have to buy it online, unless you have a speciality fish store in your area. General pet stores like Petco and Petsmart, will have about a dozen kinds of colored gravel, maybe 2-3 bags of laterite, a few bags of coral for salt water tanks, and half a dozen colors of gemstones for betta bowls, and that's about it. Because gravel is so heavy, make sure you get a good deal on the shipping costs if you buy online, or you'll end up spending more on shipping than you do on the gravel.

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