When i adopted my rescue a year and a half ago she had "food aggression" issues when it came to other dogs not people, We fed her in a different room then our other one for a very long time until she improved and now she has absolutely zero issues with dogs eating out of the same bowl as her. Lately she is guarding water bowls, its become insane, I have 2 downstairs always topped up and 2 upstairs always topped up. She loses her cookies over any of our other dog trying to drink, so i have been managing it, everyone gets to drink but she is put away with her own water dish in a bedroom downstairs. Could there be something medically wrong with her, is this something that will pass like the food issues?
Its not like they dont have free access to water, they have water all over the house its one thing that is readily available to them all the time.
Its so weird, this is the dog that will share a fresh peice of meat with the 2 other dogs with not one growl, but lord help whoever trys to drink something that there is plenty of.