I miss having a fish tank in my bedroom. I had one when I was in elementary school and it was very soothing when I was in bed, and cool to look at the rest of the time.
I don’t miss having to take care of it though. Fish tanks are a lot of effort. Also, I have a bunch of cats now. A fish tank would likely be a spectacularly bad idea now.
I probably won’t be getting a fish tank.