Aquarium gravel comes in all shapes and sizes. While gravel is the most popular aquarium substrate, all of the options may get confusing. Then when you throw in other substrates like sand and soil, who knows what to choose? Just keep in mind the following when choosing your aquarium substrate. There are only a couple key functions of any fish tank substrate. They anchor your plants and roots. They support your fish tank rocks and wood. Other than that, they are mostly just for plain old decoration. There are however, some basic things you should know about aquarium gravel to save yourself some trouble later.
Natural Gravel
Pea gravel is the most popular of available aquarium gravel substrates. Choose a size that is at least 4mm in order to get optimal performance. Gravel of this size will allow good water flow through it keeping the area water from becoming stagnant. You also need to pay attention to whether the aquarium gravel you choose is inert or not. If it is, it will say it on the package or in the description. Inert aquarium gravel should have no effect on the chemical balance of your aquarium.
Need pH?
Other choices like crushed coral that are not inert, can raise the pH levels. For most freshwater tanks, this is not a desired effect. Saltwater tanks, African Cichlid tanks, and other tanks with only fish requiring high pH levels are the only cases when you should consider something other than inert gravel. Fish tanks of this type should ideally have a pH level of 8.0 or higher. Crushed coral, marble, limestone, or other pH lifting gravels are suggested.
Sand
Sand is not usually suggested for most aquariums. However, if you insist on sand, silver sand is the most common aquarium sand and you can find it at your aquarium retailer. Silver sand is an inert substrate with of course, very fine granules. These fine granules are the biggest problem with using sand as a substrate. Sand compacts and will not allow adequate water flow and oxygenation of the water in the bed. This eventually leads to unwanted bacteria growth and root rot of your plants. If you are willing to stir your sand up every couple of days you can make sure this does not lead to problems. This is just additional maintenance that is probably not worth the trouble.
Soil
You can probably guess that soil can lead to a muddy mess and therefore is not suggested as a substrate. Although soil is probably not ideal, it can be good for plant growth because if its higher iron content. When using soil, it is usually not necessary add additional nutrients to soil. This is however, necessary for most other substrates if your tank has plants. If you do choose to use soil as a substrate, make sure you use aqua soil that is specifically designed for aquariums.
I believe natural gravel can also act as a breeding ground for the good bacteria your fish and fish tank need.
If you use sand, I suggest getting a loach species that burrows like kuhli loaches. They’ll help keep it stirred up for you. I don’t think you can use an undergravel filter with sand, but kuhlis have been known to take up residence inside them and cause problems.
Many eels burrow, also, but tankmates have to be chosen carefully, as they may kill smaller tankmates.
My fish tank has been set up for 1 month. I didn’t get the gravel placed in the tank before my children put the fish in. It seems to be doing ok. I had to buy a placo because there is more algae than my snail could handle. My question is, can I put gravel in the bottom of my tank now? Or will it hurt my tropical fish?
Hey Eva,
You sure can put the gravel in now. Check this out for prep tips.
http://www.fishtanktutor.com/keep-your-aquarium-decorations-from-corrupting-your-water
Gravel is important to establishing and maintaining your good bacteria so I’d get some as soon as you get a chance.
Thanks, I’ll get gravel asap. I know this is probably a no brainer, but do I need to take the fish out to put the rocks in? Also, my placo died after only having it for like a day and a half (it looked all dried up, although it was in the water). I was afraid we starved it to death. There is green stuff all over the bottom of my aquarium (no gravel yet) and I thought he would eat that. Isn’t that what they eat? How do I know if I need to get another algae eater or if my snail is doing the job. I have 4 one inch fish and 3 of .5 in. fish (guppies I think) in a 10 gal. tank. I don’t want to kill another placo.
Eva,
Sorry to hear about your Pleco. They do eat algae. With that much in your tank, I wouldn’t think it was from lack of food. You can add rock with the fish in there. Just make sure they’re out of the way of course. If your tank starts to fill up with algae on everything, you’ll know if you need another algae eater.
thought you like to know,I have a 2500 litre tank without substrate. just some large rocks and driftwood. currently have oscars and other cichlids.
Have not had any problems, in fact I find it much easier to keep the tank clean! I don,t vacuum the tank at all just 10% water change weekly.The wave maker moves the detritus and the cannister filters suck it up!! The tank is 1200mm deep,so a little hard to clean the bottom. Its pretty much self cleaning! Just paint the bottom and back of the tank black, looks good the fish stand out better.