yes thank you for the advice and I do get what ur saying
I really hope you do; we only want what's best for your fish.
I hope you don't find what I'm going to say too harsh, but I feel it has to be said.
and my goldfish are small
They're only small because they're
babies. They should grow into big fish.
Except your fish won't get the chance to grow that big, because they'll become stunted or die due to toxic water conditions. You couldn't physically
fit a filter that could cope with the waste from two goldfish in a 28l tank.
28l is not 'quite big. It's very small. I have water change buckets bigger than that. My smallest tank is 23l, and it houses ONE small betta (maximum adult size around two inches, with a slim body, so does not produce much waste). My two fantail goldfish (maximum adult size EIGHT INCHES, and deep bodied, so produce a LOT of waste) live in a 150l, and I would upgrade that, if I thought they needed it.
And it's not just me that thinks this. You've already had essjay say the same; how about the awareness raising group "It's Not Just A Fish"?
http://injaf.org/aquarium-fish/the-goldfish-section/what-size-tank-for-goldfish/
Or these goldfish specialists?
http://thegoldfishtank.com/goldfish-care/tank/do-goldfish-need-a-big-tank/
Or maybe you'll believe the RSPCA?
https://www.rspca.org.uk/adviceandwelfare/pets/fish/environment
and my fish seem to love it they look happy
How would you know? What does 'happy' even mean if you have the brain the size of a fish's? Anyway, fish have evolved not to show signs of distress or disease, because it attracts predators.
And yet you started this thread because one of your fish was sick.
As I said in my last post, it's up to you and your conscience what you do, but please don't come here and tell us that everything's all right when it absolutely isn't.