Thanks, appreciate it. I don't have any wrasses yet but plan on rectifying that. If I have finer sand just in the middle of my tank, would that be good enough if I did get wrasses that bury themselves down the road, or does the entire substrate need to be sand?
they'll find it, but if it spreads out and gets super thin that might be bad.
it doesn't have to be oolite sand, something in the 2 mm range should be fine. i have fiji pink. not sure on the middle range options, but i wouldn't try to use crushed coral or something like that
https://www.reef2reef.com/threads/all-about-reef-safe-wrasses-in-aquaria.259894/
that's a great general read on wrasses