Hi everyone
I noticed my goldfish sitting on the bottom of the tank on a lean so got closer and he swam to the top and it looked like he took a gulp of air and created bubbles then drifted to the bottom without moving anything and hit the bottom did the same thing again. I gave the goldfish some food he ate a fair few flakes then same thing over again(there are 2 other goldfish in tank and doing fine).
Any ideas why this is happening please?
Thanks