Aggressive BTS!

[Revalva]

I need help!! I have two BTS. I have a 7 year old very calm mannered BTS. I have never had any problems with her. I rescued her from a hoarding situation while I worked at a Vet Clinic in the Dallas Tx area years ago. She has been a great addition to my scaled babies, so I wanted to find another! Where I am located currently, BTS are harder to find. And I do not want to purchase online and ship. So when I found one I was ecstatic! I purchased a juvenile unknown BTS, who at first, was very calm and patient. I have slowly handled him/her and had gained some trust.

Recently though, the juvenile has turned. Everytime someone in my family or I walk by he/she begins charging and hissing. I cannot even change out his/her water or clean their habitat without him/her lunging at me. He/she has had no trauma to cause this change in behavior. No change in sceneries or enclosure decor. It has gotten to the point I have to use a shield to enter his/her enclosure and ensure not only my safety but theirs. Its traumatic to both of us because I cannot NOT clean the substrate and clean and refill food and water. I am running out of options and it seems to get worse everytime.

Some things about this BTS:
He/She is housed in an appropriate 300 gallon vented top, hand made plexiglass enclosure with front opening doors. So I do not reach from above. They are housed in separate rooms of my home. He/She has never seen or interacted with the other BTS and I rotate feedings and cleaning days between them so I don't contaminate.

He/She is an approximately 8mnth old classic Indonesian.