I do not understand why. Although a beta fish may actually live a lot longer than that. Not one of my best human moments but when our children were young our middle son wanted a beta fish. The pet store did not have the vases or plants that you usually set them up with, so we brought him home in a tiny little plastic box, with the intention of buying the vase and plant when they came in. We did buy him food. Well I was cleaning their room later that day and I put the fish on the shelf in their closet so I didn't accidentally knock it over. I placed it carefully between Winnie the Pooh and Tigger on the shelf. Well that poor little bugger was up there for a month! I'd forgotten all about him! I felt horrible! I immediately got him the vase and plant and he lived for years!