it might be as we are suspecting and just needs time to adapt to his new home, or may simply not be hungry.
in this case, just leaving it be for full week before trying again is best, and if refused wait another week, don't try teasing it for more than 10-15 mins if no inetrest is shown..
now :-D lets attack the RI issue...
it's hard to guess wihout seeing or hearing it myself.. so before going anny further with info..
if you do suspect an RI the best course of action would be to find a good herp vet (make sure they know snakes) most vets don't and only go with little experience they touched at vet school regarding exotics..
a very mild RI can go away on it's own with raised temps, but in the majority of cases you will need antibiotics to get trough it.
and the earlier it's caught the better.
the vet should do a complete check up and listen with his scope at the lungs as it's breathing, this is to see if he hears any ubstructions.
next of course will be to open his mouth to see if any mucus is present.
( you could do this at home if you want, it would give you an idea)
if he suspecxts something, he should do a swab and culture to find out what else could be attaching to the RI..
now all this said, the culture, if the vet has experience, the results would tell him witch medication to prescribe.
problem is!!! most times they prescribe before getting the results with the hope that the meds they give is the right one.
there's a few diferent ones.
1-baytril = enroxil = enrofloxin is often given and can do tissue damage/burn like sensation if wrongly administered
2- fortaz I think it's a third gen medication and covers a wider spectrum, it also has slight side effects but is better,if the vets mentions both go with this one.
no harm in asking him about either one, he will see you know what you are talking about and may call on coleagues to get a second oppinion, this also gives you a chance to check his knoledge with herps..
3-a few more meds out there but these are the most comon ones
they will both do the job unless one doesn't cover the virus/bacteria the snake has.
now this of course will all be $$$ and is the course to take if your GTP is in fact sick..
now ( i hope i won't get flamed for this ) if you know what you are doing and have experience, and I CAP the KNOW WHAT YOU ARE DOING PART
there's one place in the USA where you can order baytril 2.5% in a 7ml vial. search (beautiful dragons) most other places you need a vet prescription to get it.
you can get the syringes there too, but these i would recommend a pharmacy get the insulin .3cc 31 gauge needles, the snakes barely feel them going in and makes the job that much easier.
then you need to make sure you're giving the right dosage, for this you need the snakes exact weight.
once all this is confirmed and you are ready..
you must inject the snake with a I M injection, (in the muscle) in the UPPER 1/3 of it's body or at the very least UPPER 1/2.
too low and the meds are filtered out by the liver and are innafective, they can later create liver problems..
it can also be done oraly , but you need bigger dosage and it's not as effective, most of it is digested..
injections with baytril would be 0.?? cc every 48H for a total of 10 injections.
fortaz is usually every72h
injecting about 1/4" off the side of the spine (depends on the size of course) at a 45 deg angle or slightly more going in towards the front between scales.
once in, inject and it will produce a small lump, you can massage that the ease the GTP a litte, then put him back in.
try to inject in diferent areas each time.
shouldn't be the case with a GTP but for bigger snakes, if the dose is bigger than 0.4 it's best to split that up in multiple shots..
NOW DON"T TAKE THIS # FOR GOLD

but for an idea on a 2 year old GTP
you would be looking in the range of 0.07cc to 0.15cc again this depends on the size, i'm just guessing here to give you an idea.
so with all this said !!
if you have serious doubt that it could have an R I, best not to wait too long before seeking the help from a specialized herp vet.. if it gets out of control, at some point, it's hard and next to impossible to recover from it..
I'm crossing my fingers for you that all is well, that' it's in perfect health and just needs time to adapt
sorry for the long read LOL
Steph