I got a text at work last night to say one of our goldfish had died. However when I got back (to discover Dh had left it for me to deal with!) I realised it was still alive. It seemed to be "hiding" beside the filter and only moved when I shook the tank gently. It swam about quite happily but didn't feed much.
This morning it's doing it again. Seems to gravitate to the filter and putting its nose in the gap between the back of the filter and the tank. If I coax it, it will come out but next time I check it is back there.
What's going on???