Last year we had a sad attempt at raising a single fish in an aquarium. He didn't last long.
This week, my wife and kids took it much more seriously and prepped a nice tank that now has five tetras in it. They seem quite happy, with live plants and colourful gravel, as well as a quiet high-tech filter that is keeping the water beautifully clear.
I'm quite enjoying the burbling sound and spending time watching the little tropical lake fish swimming around. The girls check on them regularly and feed them morning and night. I think we'll get some more fish soon. It's certainly a lot easier than a dog.