I have two tanks now that have just a sand substrate.
The plants do soso..

I have been thinking of starting a new tank getting it
well on its way with the plants and then redoing the other
ones. I keep goldfish.

I was wondering if using peat as a base with a layer of sand then
small pebbles over the top would be good for the plants and not
have a negative impact on my fish.

Any advice on this?

Azul