Spot the Goldfish's swim bladder problem cured

Spot is a fantail fish who used to have a black spot but like most goldfish he has turned mostly orange. 

Spot's two friends

He was swimming strangely lately and having trouble keeping upright or getting down to the bottom of the tank to feed.  He looked unhappy and it was a lot of effort to swim. We looked it up and found that he must be suffering from a swim bladder infection.  It can be caused by over-feeding, bacteria in the water or constipation.  Here he is having trouble swimming.

The cure was in four stages. We changed a third of the water in the tank (replacing it with water of the same temperature) and then fasted the three fish.  We gave them no food for a whole day.  The next day we fed them a pea each (a frozen pea defrosted and cut up with scissors).  Then we added some special internal anti-bacterial liquid to the tank which we bought at a pet shop.  We asked for something to cure swim bladder infections.  A capful of it needed to be dissolved in warm water first, the added to the tank.  After two days we fed the fish normally, and changed some of the water again.  On the fourth day we added more anti-bacterial stuff.

On the third day Spot was cured!  He was swimming nicely again and had no problem wandering around at the bottom of the tank.  He seemed happier.  Here he is!

Spot swimming freely again.