I “once” had a Sleeper Goby. It looked more like Tinkerbell flying over Cinderellas castle spreading pixie dust. It was a mess. Three days it took me to catch it! I know.I have a ton of sand sleepers. They won’t even fit in a tub together lol At least not peacefully. Two of them grow to 9 and 10 inches lol I am sure they won’t get that huge in captivity but they are getting bulky.
I think it would be risky to do with more fragile leopards and Anampses wrasse but probably fine for those with the more popular/common sand sleepers that are pretty forgiving.
Bonus is the sand harbors spaghetti worms which the Copperband loves.
The sand would never stay in the tub either. My bigger wrasses throw it all over the tank and buries corals! It’s actually my kuiters leopard who is the worst offender of tossing sand everywhere. I would not have thought a leopard could be so destructive.
She will actually dive into the sand even when not sleeping and flop around like a beached whale to toss it all over. She does this to stir up pods and worms.