Sandy Decisions

[Europhyllia]

There is a difference between sifting a burrowing. Some gobies sift meaning they take the sand in the mouth with the intent of getting small critters out of it to eat.
Very fine sand would work for them. Truly burrowing fish (those that create a tunnel/home in the substrate) like jawfish will need a mixed substrate that include larger shells etc because you can't build a tunnel with just fine sand

[CoryDude]

The same bacteria and microfauna will be the same on most substrate types. I just re-did my tank with caribbsea reefsand plus, which has a lot of shells and larger pieces mixed in. Personally, I love it and love the look. I plan on keeping a pistol shrimp in there, so the shells and whatnot will make it that much easier for him to build his tunnels.