Hi people
just through say hi im from the west midlands
here my fish tank
my tank is think about just over 7 gallon
Welcome to tff!
and nice tank! Looks really natural and your fancys look really healthy.
The goldfish though will grow to atleast 6 inches, believe me, I have had all those varieties you have in your aquarium.And as they get bigger they will make much more waste and the water will become polluted, slowing and stopping there growth so that they do not reach there potential, they may also get deformed spines as they will get large enough that they will barely be able to swim around that tank.
A 30 gallon tank would be great for them, elimination the above problems, and you could keep the existing filter & decor, so it wouldn't cost much atall.
Anyway you may already know this so if you do sorry lol.