i worm everything new, just for peace of mind. mainly just in case they have any latent worms or immature worms that are not reproducing therefore i wont pick them up on fecal checks. but then i leave them be and only check if they do anythign weird which isnt often, neither age or species matters really. the dosage changes though. it wont hurt them but you can jump down to your local vet and get them to do a parasite check before treatment if that makes you more comfortable