A 35 gallons tank is an enclosure that should be used for an adult and I would not recommend to put a BP in a 35 gallons unless it is at less 500/600 grams as a minimum.
Yes you can fill up the enclosure but in reality for some (the MAJORITY) animals it just does not work and the first sign is food refusal.
In a young animal food refusal needs to be addressed very quickly as it will become a vicious circle and you do not want to reach the point of no return.
Get a 10 gallons tank or a 6 to 12 quarts tub and lower your temps on the hot side to 86/88 and 76/78 on the cool side, wait a week and offer food, depending on what the animal was feeding on previously this is what you will need to offer, if it was mice feed mice if it was live feed live until the animal is consistent and eats for you.