As babies they can be aggresive, but after acclimation and are feeding well then regular handling they calm down. Only 1 out of 14 bloods I've kept was fiesty every once in a while. CB always helps and from a reputable breeder, or even someone here on the forums. They wouldn't lie about a blood being dog tame and ruin their name. My worse snake I've owned was a female ball python, she never stopped bitting. If the ambient air gets below the high 70's they can get sick, RI, Respiratory infection, along w/ low humidity. Keep a hot spot around 85-88 cool spot 80 and keep humidity 60%-80% and your set. Rubbermaid tubs or rack systems work best as humidity is easier to keep up. Don't use an aquarium unless you plan on misting constantly and run a almost closed top. I've used them but you have to keep up on them. They do like to hiss sometimes when you go to pick them up but they are just talking to you, and thats what bloods do. Its not like they are all coiled up and ready to strike hissing at you. They are the best snakes I think and still have a bad name for no reason than someone buying a wc back in the days. Reds get the biggest, borneos second and blacks are usually the smallest.