There are many different kinds of substrates available for fish tanks (i.e. sand, gravel). I've even heard some people say they don't use any substrate for some of their tanks.

Is the substrate in a fish tank purely aesthetic, or is there some purpose to having it?

  • Does "substrate" = sand and/or gravel? Oct 27, 2014 at 16:50
  • @JamesJenkins Yes. I think the definition is actually "The bottom layer".
    – Spidercat
    Oct 27, 2014 at 16:54

1 Answer 1


Essentially, for beginners, substrate is purely esthetic. The filtration purposes attained from a deep sand bed or whatever rocks used as a substrate isn't something imperative for the well being of most aquariums. Even more, usually beginners will not be dealing with animals or plants that are dependent on a specific kind of substrate.

As for more advanced keepers, or keepers with organisms that are substrate dependent, then missing a substrate can lead to the downfall of an aquatic ecosystem. Some animals are especially dependent on sand burrowing and their well being may depend on this habit. The number one thing that tells you whether the organism is dependent on the substrate is if it has evolved in some way in order to sustain itself with the substrate in a propitious way. Some organisms may simply take advantage of a substrate in it's environment, but that does not mean all of this species needs the substrate, as it may vary in different geographic locations this species has spread to. Substrate can alter the water chemistry, softening, or hardening the water, and affecting the pH. Though the substrate can have a discernable contribution to the biological filtration, this can be made up for in the filter itself. Also, substrate may be important for hibernation, many animals such as frogs and turtles wil dig in the substrate underwater and hibernate if temperatures are very cold. Owners of outdoor ponds in countries with cold winters should provide their pond inhabitants with a substrate appropriate for their hibernation needs.

Essentially, you'll only need to be specific when it comes to the substrate when your tank inhabitants are reliant on it. It is worth noting though that even organisms not reliant on a substrate may prefer a substrate.

  • interestingly in Europe a tank without substrate and plants is considered something for experts, and heavily planted acquariums are the norm for beginners because they're much easier to get and keep stable.
    – jwenting
    Oct 28, 2014 at 15:40
  • @jwenting I guess in a way or another this may be true. Tanks with substrate and plants are more complete when it comes to the nitrogen cycles and thus require less bio filtration from the filter. So in terms of filtration you need a better filtration system for a tank with no plants and substrate. However a substrate can be hard to maintain clean as uneaten food and stuff settle there and are hard to clean, while plants can over grow or get eaten by inhabitants, which makes a real mess.
    – Mozein
    Oct 28, 2014 at 17:17
  • @jwenting my verdict is filtration technology, though rather expensive, makes it easy to maintain an aquarium without substrate and some plants. While for plants and substrate, manual work is more intensive.
    – Mozein
    Oct 28, 2014 at 17:19

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