did you try the mellow yellow hostel? i´m still here at the hostel, i´ll ask about availability if you want me to. the website is http://www.mellowyellow.com.br/ - this place is great, i´d recommend it. i´ll ask the owner if he´s heard of the crab hostel and report back!
i stayed at crab hostel this january and i can recommend it.
its located at ipanema in the seconde parallel street to the beach, so it is good located.
on arrival: if you are looking for the hostel, orientate yourself by the house number as the hostel has no big sign with the name on it. i think that's for safety reasons.
Hi. I stayed at the Arpoador Inn and highly recommend it.
It is the only hotel that is on the beach side of the street.
It's around 28USD per person (55 for a double room).