Goldfish in 55 gallon tank

[Newlyobsessed]

Do I need to have gravel/sand covering the whole bottom of a 55 gallon tank n tank? I just bought a used one and plan on just transferring what I have in a 7.5 gallon to the new tank. Should I buy more or can I leave it bare? I have 4 marissmo moss balls to put at the bottom.

 

[Toad]

Goldfish like sifting through sand, gives them something to do. Pool filter sand is very cheap, you just want to make sure you rinse it really, really, REALLY well before you put it in. I wouldn't go more than maybe half an inch to an inch deep unless you're planning on fake plants (which may need some small river rocks at the base of them if the goldie likes to dig or pull them) then maybe an inch and a half.

Edit: if you want darker sand, check out black diamond blasting sand. It will really make an orange goldfish pop