I have bought a property that has a tiny decorative pond with waterfall and sizeable filter. It looks as though a larger pond use to be in its place.

I plan to install this product: https://www.primrose.co.uk/500l-mayfly-preformed-pond-p-67263.html

I then plan to plant a mix of oxygenators and decorative plants (lilies) and then stock very lightly with some small, hardy goldfish.

Can anyone recommend what I should line the floor of the pond with? i.e. should I have part gravel, part soil, then let it settle? I am guessing that common garden soil and then small gravel to a thin depth is all that's required and then let the water clear before planting and adding fish

3 Answers 3


Keep it bare bottom and use pots for any plants that you add to it. Unless the pond is permanent like concrete and I would still be hesitant to suggest it, using a substrate in a pond is unnecessary and can be a complete pain to deal with. There are pots specifically made for pond usage that have slats or holes in them. IME, these are by far the best way to setup a pond with plants in it.

  • I might add just add a few rocks for decorative effect
    – Steerpike
    Commented Jan 11, 2019 at 10:22

It is best to keep the bottom of a pond as clean as possible. You will need to do a spring clean every year to remove the waste like leaves and other stuff.

Goldfish are known to dig and to eat plants, so even the flower pots need to be covered by heavy rocks or other types of covering. Also, you need to expect some loss of plants during the summer.

It is best to use sump plants in a small pond like yours; underwater plants are at risk of being eaten.

The maximum number of fish you can have in a 500 liter pond is 4-5 goldfish or 5-10 of smaller types of fish and you will need to have filtration of the water.


You can forget about any layers with goldfish or Koi because they will mix it. Generally plants are put in pots, often with large gravel on top to try to keep the fish from digging. The liner in the figure is generally too shallow for water lillies; about 2 + foot (60 cm) is minimum depth; except for some special miniature types. I put no gravel in my pond system, that has worked for 20 years. Often there is an algae bloom / green water in a new pond, which I do not try to fix as it has not lasted long. And, I suggest some floating plants like hornwort, Anacharis and duckweed. I suggest getting a book or two on home ponds.

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