My mistake...and a little goldfish died in our fishtank sometime between 1am and 7am this morning. I thought the more water you give the fish, the more they'd have to swim and play around in...but no, apparently the amount of water somehow blocked off the water circulation vent, and I think it starved the fish of oxygen (if that makes any sense).
The other fish are doing alright, it seems. But as I was about to go to bed last night, I saw the 'littlest' fish on its belly. It was still alive, more or less, but heaving. You could see it was still alive, as its eyes rolled and now and then its fins seemed to waddle a little (or was that just the water current making them move?). Imagine the pain and suffering it had to go through, those last moments of life, choking and suffocating in water, and unable to control where it was going...
Poor fish, it died because I wanted to give it more room to swim in... guilty.
Time to give it a proper burial in the garden.