Hoix are eating machines. Anything organic will do, they’re even less fussy than weevils in that respect. In fact, a Hoix is probably the only creature anywhere that would eat a Weevil.
About the only thing safe from a Hoix’s appetite is another Hoix. If that weren’t the case, they’d each themselves into extinction. The hunger of the Hoix is legendary.
The one in Torchwood’s cells is no exception; it can eat its own bodyweight every day and still want more. Torchwood would be facing bankruptcy from feeding it, but for one thing.
It’s a really excellent garbage disposal unit.