Curiosity101
Is now at University! :D
For comets I'd personally aim for at least 30gal per fish so that's... 150gal long term? 550-600l? They wouldn't need this straight away but they would need something along the 200l mark asap. And then would need upgrading later to avoid health problems. They will also need double filtration, and don't go for tall tanks, they need the surface area for gas exchange.
For the fancys the general rule of thumb is 20gal for the first and 10gal for each additional so for your two you're looking at 120l minimum. And there is no gaurantee they wont outgrow it. They'd probably be ok in an 80l for the time being if you wanted to do two upgrades, but again you'd be risking health complications like stunting.
Have you read the information on cycling? If you haven't then I doubt the fish will survive long enough for you to buy them an upgrade.
The two fancies are probably just getting a bit nippy with eachother due to being in such a small tank. Also the water quality is probably getting to them. Black patches sounds like ammonia burn to me.
Oh and just a note, try to go second hand for tanks. It's much cheaper and there are a huge amount of sites you can look for them on. Searching 'classified ad' in google should get you started. There is also the classifieds on here and also ebay.
Edit: Forgot to mention. Goldfish don't get pregnant, they get 'eggy' ie. full of eggs. I very much doubt yours is eggy due to it's age. It's more likely that it's just slightly more round than the average fancy or it's bloated. If you try it on some deshelled peas the fibre will hopefully help remove any blockages. To get the pea ready just stick it in a microwave for a few seconds till it's soft and then pop the fleshy inside bit of the pea out and feed them that.
For the fancys the general rule of thumb is 20gal for the first and 10gal for each additional so for your two you're looking at 120l minimum. And there is no gaurantee they wont outgrow it. They'd probably be ok in an 80l for the time being if you wanted to do two upgrades, but again you'd be risking health complications like stunting.
Have you read the information on cycling? If you haven't then I doubt the fish will survive long enough for you to buy them an upgrade.
The two fancies are probably just getting a bit nippy with eachother due to being in such a small tank. Also the water quality is probably getting to them. Black patches sounds like ammonia burn to me.
Oh and just a note, try to go second hand for tanks. It's much cheaper and there are a huge amount of sites you can look for them on. Searching 'classified ad' in google should get you started. There is also the classifieds on here and also ebay.
Edit: Forgot to mention. Goldfish don't get pregnant, they get 'eggy' ie. full of eggs. I very much doubt yours is eggy due to it's age. It's more likely that it's just slightly more round than the average fancy or it's bloated. If you try it on some deshelled peas the fibre will hopefully help remove any blockages. To get the pea ready just stick it in a microwave for a few seconds till it's soft and then pop the fleshy inside bit of the pea out and feed them that.