About goby's ?can you keep without sand ?

Im woundering if i can keep the goby's in QT tank without sand while i clean and recycle the 90gl?
Im afraid it will be tight quarters with the corals that have survived the "invaSion of the spiders" and i dont want them all messed up .
I have taught them to eat foods ,shrimp pellets ,flakes ,shrimp so i dont think food would be an issue.
Would be temp 2 months tops ,so i can cycle again .
Thanks
orange spotted sleeper goby's
i could keep corals in mesh baskets hanging ,not nice to look at but its another option

Yippie ...................Now 1 more question ...when i put them back they will start sifting again right ? i got them because they are great cleaners ,just awesome

Thanks a bunch .....i would say mine are full grown too and thriving in the main tank .
I dont think they will be happy in the QT but i really want to keep them .
TY