Hi everyone, just need a bit of advice regarding my goldfish, at christmas, I got 2 small goldfish (approx 1.5-2 inches in length not including fins) and now I have bought a comet who is about 2.5 inches long excluding fins!

My tanks dimensions are 40cm by 20cm and about 25 cm high. I have been told it is a 20 litre tank!

So far the fish seem happy, although one of my goldfish has a white bubble inside its eye, which I am treating from today with medication.

I am just worried this tank is not big enough for them, or is it? I have no idea about goldfish and would be grateful if someone would answer the following questions, thanks...

1. How long will the Comet get if its in this sized tank with 2 other fish?

2. Is this tank the right size for all 3 of them?

3. What exactly does my goldfish appear to have (with the white bubble in its eye)

4. My tank has a filter and an air pump, but are there any other ways to keep the tank safe from disease aand nice for my fish to live in? I heard adding salt to the tank lowers the ammonia produced my the goldfish faeces!

Thanks so much

Matt