Sand Substrate For Goldfish?

[blappy]

Goldfish are very greedy and constantly look for food. I see they always dig in the gravel. I'm afraid they'll swallow sand and develop complications. Should I put sand as substrate or just use gravel? I saw some planted tanks use sand with goldfish.

I wouldn't want my widdle babies getting scratched up from the inside by icky sand :3

 

[fluttermoth]

Goldies are better on gravel, as sand can irritate heir gills. You just want to make sure that's it's a fine gravel that can't get stuck in their mouths.