
to TONMO
while it's possible to put a dwarf species in a 29, they don't really make good pets, since they tend to be nocturnal, shy, and short-lived. If you're planning from the start, a 55-75gal tank with a sump would be your best bet. We used to think a 29gal was OK for a single bandensis cuttle, but a few people said that as full adults they seemed cramped in a 29.
You can get some idea of the best possible dwarf experiences by looking at the threads about trapper and varys and their offspring, but note that their owners only got to see them in the middle of the night using red lighting... it's a much less interactive pet than a larger octo.