about 6 months maybe a little more. i plan on collecting various upper jaws though and keeping them for many years to come should my circumstances not change.
I've kept polys since about 1980. Back then the only species available were P. palmas, P. senegalus, P. ornatapinnis, and P. delhezi. Mid-80s brought us P. retropinnis and P. weeksi into the hobby.