Siphon Ray (25 gp; 2 lbs.)
This parasitic, hand-sized, cartilaginous fish attaches to a creature and filters nutrients directly from its host’s bloodstream. However, a siphon ray reoxygenates the blood in the process, allowing the host to hold her breath for twice as long while underwater. A siphon ray must be attached for at least 1 minute before providing this benefit, and every hour a ray remains attached per day, the host must succeed at a DC 15 Fortitude saving throw or become fatigued. While attached, a siphon ray avoids most attacks as though it were a piece of equipment unless specifically targeted.

A siphon ray must be kept in at least 1 gallon of salt water when not in use. If it is out of salt water for 1 hour, the siphon ray expires.