for my 75 gallon tank, it will be a reef what should I get for a clean up crew? I don't want hermits, so what types and how many of each snails shut I get? I have also heard emerald crabs r good. Shut I get one of those?
i would get about 15-20 tongan nassarius snails 10-20 astrea snails 5-10 nerite snails i dont really like emerald crabs because they do get bigger and get more aggressive and i have had them pick at my blackcap i used to have when he was in his cave so if you have fish that like to have a little home in the rockwork i wouldnt get them other than that they are beneficial to your tank i dont think most people have any problems with them and u could get like 3 of them if u wanted
For Snails I would start with 5 Cerith, 2 Nassarius vibex, 5 Stomatella, 5 Strombus maculatus, and a single Fighting Conch.
If you like Emerald Crabs then get one.
nassarius snails.. emerald crabs.. maybe shrimp? fire and cleaner shrimp are my faves. the emerald crabs eat algae so just make sure they have enough to eat.