[xdude]

As much as bare bottom tanks give the fish more space to swim. I really don’t recommend them.

Many species of fish don’t have teeth, and hence they rely on gravel to “chew” their food. That’s exactly why you tend to observe them “eating” gravel and eventually spitting it out, they’re not mistaking it for food. They’re using it to break the food they’ve eaten into smaller bits, giving the effect of chewing the food.

Moreover, gravel in fish tanks tends to hide any poop or food remnants that have sunk into the bottom and aren’t within the reach of the filter. This looks much more appealing then having a pile of poop on the bottom of a bare bottom tank. It also plays a role in the break down of the poop and eaten food.

In addition, it increases the surface area for good bacteria to grow. Now i do have ceramic pieces in my filter which also do just that, but gravel tends to also help.

Somehow I missed some of my favorite topics. All these things depend on the type of fish, size of the tank, etc. There are types of fish that need some sort of gravel or sand. For example Loaches, Cory cats, etc do need sand. Some of these fish don't feel comfortable unless they can high under sand some time to time. It's their way of having short vacations. Also there bottom-dwelling fish like some types of Cichlid who prefer to dig holes and lay eggs.

But there is plenty of other fish which doesn't need sand or who would make a mess of that. A good example is DiscusFish. People think they need an Amazon-like environment with sand plants driftwood etc. But in reality, if you want Discusfish which look bright with no dark spots of patches and super healthy then bare bottom tanks are the best for them.

Even same goes for fish like Goldfish and Carp. Oh many don't even know Goldfish have big teeth. You can find fallen Goldfish teeth at bottom of the tank sometimes.