hi i am wondering what is the hardest thing about keeping a bimac octo. and are bimacs hardy at all.

The hardest thing? Probably learning to deal with the short life span...it can be difficult to deal with for some keepers. If you mean, what is the hardest physical thing, it would be maintaining correct water parameters...a lot of saltwater experience is a must to keep cephs...but once you do, you are hooked!!! Bimacs are great as captive octos, once you get the tank set up correctly...be sure to check out the ceph care check list !
greg

...probably learning to be patient and taking the right amount of time to get the equipment and let the tank cycle...