Giardia is a bit of a big deal and as far as I know is not a ‘normal’ part of their gut flora. . After he’s had a couple of doses of the med, you’ll need to do a thorough disinfection of his enclosure and replace his live plants, branches and vines. I’m not sure of what the standard method of disinfection is. I use a combination - first a dilute bleach mixture, rinse and then F10 veterinary disinfectant and a rinse and a sun dry. I’m probably overdoing the disinfection, but I prefer to err on the side of caution. Do make sure to get at least two clear fecals after. I got only one and just had to have my guy retested because he was showing symptoms and that crap is back/still there. Next week I’ll have to take down and disinfect his double sized bioactive enclosure.