My dad and I made this fishtank for my mum for Christmas a few years ago with dollhouse furniture. I thought it was pretty rad
Edit: Anyone wishing to recreate this should be extremely cautious. We tried to make sure everything used was aquarium grade - no tight spots (for big fish) or sharp edges. We had no fish injuries in the two years it was running but I definitely will say it isn’t the easiest tank to maintain in terms of the biological filter. I work with fish, so I knew what to be wary of - but if you’re careful it looks rad and your fish *should* be fine.