neurotic goldfish owner!

[wigparty]

Hi all,
I posted here with general golfish questions and you were great. Can you help with this?

One of our goldfish is silver but has recently got a dark grey line on the very outer edge of its back fin (tail?). It doesn't look like it's rotting which is why I didn't think it was fin rot. Any ideas?

I was going to post on a goldfish site but they ask for so much info I just don't have (nitrate, nitrite levels etc. etc.).

We change 20% twice a week, treat it and the tank has a filter etc.

Can anyone offer any suggestions?

Thanks in advance!

Message withdrawn

Could be pruners, thanks! He seems in good spirits and is eating well so maybe it is nothing serious. Might pop into goldfish shop this week just to check...
thanks again!

I have a silvery one to that is changing colour, like flecking.

Hi sullysmum,
apparently the colour changing is normal as they get older. My silver one is weeny and young though and the shop does think it's the start of fin rot as it's so defined at the tip of the tail .
Have bought this bizarre treatment that you have to add to the tank every day and it turns the water green, obviously harmless though (...I hope).
Hopefully he'll be bouncing back any day now.

It's the copper in the medication that turns the water sl green (if it's bright green then check your dosage). If you have a carbon section in your filter you should take it out - assume the shop will have mentiond that?

Wigparty, wonder what colour he/she will go,i have the silvery one and one black moor and one white/gold/black patterned, they are cute fish but very dirty!

It's not bright green, but quite green. Have hopefully got the dosage spot on. No carbon section in filter so that should be okay. They seem happy enough , thanks bamzooki!

Sullysmum, they are cute aren't they (and yes, very dirty)! I do hope this treatment will stop any possible fin rot.

Good luck.