|Spot's two friends|
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.