One of the biggest decor decisions you can make when planning a new tank is whether to go barebottom (no substrate at all) or to go with gravel or small rocks.

Each has various advantages and disadvantages with the final decision resting primarily on the aesthetic you are going for. Here’s the main points for you to consider when making the decision to go barebottom or gravel:



by DebG

  • Much easier to clean
  • Slightly more swimming room for the fish
  • Less bacteria colonised inside the tank without a substrate to live on
  • Natural behaviour of goldfish to root around in the gravel all day isn’t observable (unless you use gravel in pots)
  • Effective way to reduce dissolved organic compounds (responsible for yellow water) as there’s no debris caught in gravel
  • Plants must be kept in pots and like indoor terrestrial plants are restricted in root growth.
  • Algae breakouts more noticeable due to increased exposed glass areas



by cjdevesa

  • cleaning requires gravel vacuum
  • bacteria able to colonise the gravel and offer additional filtration
  • potential build up of debris and build up of dissolved organic compounds unless gravel itself is regularly cleaned
  • ability to keep plants without pots
  • goldfish able to keep themselves entertained sifting through gravel all day
  • if gravel too small potential for goldfish to choke or get gravel stuck in their mouths
  • if not cleaned algae can set in and take over gravel feeding on debris build up
  • if sand is used as gravel potential for air pockets to develop and release harmful toxins upon escaping the substrate
  • variety of colours available offer ability to customise the look of your tank

As you can see there are pros and cons of both systems and at the end of the day I really think it comes down to personal preference.

I have only ever run substrate tanks with gravel as I find the bare bottom setup a bit sterile and ‘modern’ for my tastes. I like the jungle look with lots of plants and even though you can do plants in pots with barebottom, I find it’s much easier with a gravel/soil substrate.

Colour wise I favour darker gravel (black to dark grey). Having used white before I find that it reflects light too much which washes out the fish colours and tinges the water ever so yellow.

With a regular cleaning schedule though either option can be made to look great and provide a safe and healthy environment for your goldfish. The hardest part is deciding which setup to go with!