I'm the one that was asking about my Dad's goldfish, sorry I forgot if I said the tank is 21L or 21g. It's definitely 21 gallons not litres.
First part of this ask:
Hi, my dad has a goldfish I'm worried about. She's about 17cm nose to tail tip and she's at least 8 years old. His tank is only about 21L though which I know is too small. A few months ago I bought her a fake barrel toy and ever since I put that in her tank she has been so much more active, swimming in and out of all the holes in it and she sleeps in there. But it takes up 1/3 of the floor space and I worry there isn't enough room with it in for her to swim around. What is more important?
First off PHEW I’m glad it’s gallons not liters! 21 gallons for a single goldfish actually isn’t terrible. In my (and many other) keepers’ experiences 15-20 gallons per goldfish is generally sufficient to keep the water quality good between weekly water changes.
That said, even if the water quality is good 21 gallons is still a pretty small swimming area for a 17cm fish. But, if your worry is her not being able to swim around, but she swims around a lot more with the barrel toy, then it’s actually helping her achieve that, isn’t it? I’d be concerned if she were scraping herself on it but otherwise you make it sound like it’s encouraging her to be more active in an otherwise cramped space. I hope she can get a bigger tank with friends someday, but for now it sounds like the barrel toy is providing important stimulation. Glad she seems to be having so much fun with it. :)














