My advice would be don't, because there is a chance one frog could harbor a pathogen and get all others sick. If that is not a consideration or plan to breed them, then it depends on the species. C. cranwelli and other small species, could fit 4 males or 3 females. C. ornata and C. aurita grow bigger so maybe 3 males or 2 females. Good luck and do divide the tank as Lija recommended in post no. 3 !