Territorial with water dish

[Leviticuz]

When I first brought home my Hognose, he hissed and did a false strike when I transferred him to his new home. A month went by with no aggressive behavior, whether when picking him up or feeding. He still stays passive unless it involves his water dish. Every time I refill or go to clean the dish he gets aggressive and starts hissing. Even coils up in strike position.
I really wonder why?

[akane]

I'm not sure if snakes can develop the same types of "cage aggression" mammals can but they can get confused about movement and act defensively or in feeding response.
I have what is usually the most laid back bull snake of any out of that entire species group I've seen so far when she knows there is only human movement around and yet she attacks pouring water. She also has a really strong feeding response so if you have an object in your hand it might be food and sometimes she goes ahead and tries to "kill" it without waiting to examine the difference. She's just really alert compared to my others and you have to watch her because while she's never even hissed at a person occasionally in mistake of there being a non-human items or food source she'll launch from anywhere. She even went over the back of a rather wide slab of slate hide I thought she was safe sitting under the far side of. It's my only snake that doesn't determine food from no food in existence very well. I'm waiting to see if she just adjusts and sort of grows out of it since she's young.

[TeamSlitherin]

Is it just when you touch the water dish, or also when you spot clean the enclosure/touch other things? My young scrub is very cage defensive, unlike every other snake I've ever handled. He doesn't like you to touch any of his stuff and can only be picked up sans-hook if you sneak attack him while he's sleeping in his hide! Out of the enclosure, he's a totally different beast. But for some reason, once he crosses the threshold into his lair...watch those fingers!