I think maybe one or two might be possible if you can keep them fed. I haven't kept a live oyster yet, but, have had live mussels in my tank for 7 months now and they seem to be doing well. I feed them bottled plankton that I buy from my LFS, but double the recommended dose of the bottle (because I am keeping sea squirts and barnacles too). It's a bit expensive, so one day I may try and culture my own phytoplankton, but that is down the road. I may try a live oyster some day, we will see.