Goldfish. Came back from the brink but got black edges on his fins.

[Pancakeflipper]

Over a week ago I noticed the 2 goldfish were not eating or chasing. One developed red spots and red streaks some surrounded with white areas. Went to a petshop and the guy wasn't sure if fin rot or ulcers so gave me something called 'Melafix' ( I think that's what it is called - blue strong smelly stuff - a generic medication). Did frequent water changes fish was ok but not improving. His fins showed areas of damage.

3 days later went to a different petshop who advised me to use a anti-fungal/rot medication. So bought that. They said to not use the Melafix but swop straight to the anti-fungal med.

2 days later the fish looked dead. He was pale, not swimming, floating on the surface. Did a change of water, returned to using Melafix medication. And hey presto he came around and 1 week later is eating, swimming, playing with his fish friend etc.

Except today I have noticed that on the areas of his fins that were greatly damaged are now black (only the damaged areas - rest of the fins ok).

I stopped using the Melafix 3 days ago but this afternoon done a water change and added some medication in again.

Help!!!

Evening.

Can you tell me a bit more about your fish and tank, how many fish do you have and what types, how big is the tank, what sort of filter have you got and when did you last do a water change? If you have a water testing kit then what were the last water readings? Sorry for all the questions, just trying to narrow down what is wrong.

I would not add any more meds yet, combining meds can be messy and end badly. Black marks sounds like ammonia burns to me so that can usually be cleared up with a few water changes. There are likely to be other things wrong though if the water quality is bad enough to cause ammonia burns.

What was the anti-fungal medication that the second shop sold you?

Hi and thank you.

We have 2 run of mill goldfish ( but of course they are gorgeous).
A small tank (15 litres)
The filter is a very basic one. No carbon filters just a sponge/foam thing.

I exchange 50% water every week but I have to confess to forgetting the week before they got sick. When I change water I use tap safe.

The 2nd lot of medication was a Tetra anti-fungal fin rot medication.

I bought some water testing strips today. Ashamed to say I dipped a strip in and couldnt figure it out exactly. Going to try again tomorrow when I find my brain. Or see if I can find one for dunces.

Have done a water change this evening.

Would the blackness appear after the 'illness' or are they still sick?

The blackness is an injury rather than an illness although high ammonia levels can cause all sorts because it screws up their immune system.

You might need to sit down for this bit- their tank is way way way too small. Goldfish get massive, they don't grow to the size of their tank. Have a read of this about tank sizes and this explains some basics about water quality. 15 litres is tiny and although small tanks are often marketed at beginners it's actually a total bugger trying to keep the water quality stable enough to keep fish.

When you clean your filter do you use tap water or water taken from the tank?

Post the water test results on here when you've got them and I'll tell you whether to panic or not

The filter - I clean it in the tank water I have removed.
We have 2 fish ( have I said that already?).

And I have a feeling you are totally correct about the tank size. The fish were bought for my son in Feb as a present ( we agreed to the gift). They were tiny but are double the size now.

So the ammonia will have obviously increased. So keeping good water conditions is going to get harder isn't it? And it's not fair on the fish is it?

Oh blimey DP will freak.

180 litres for 1 fish????? Fffing hell.

Yeah, I know, I was the same when I found out! When you see how big they get and how happy they are in a big tank though you'll know it was worth it. If you haven't got space for a big tank then is a pond an option? It does need to be fairly big and deep though and some people don't want a pond if they have young DCs. Do you know anyone with a pond that could take them?

If your DS still wants fish then there are loads of fish that don't grow very big, minnows are brilliant and only need a 60 litre tank (about 2 feet across) for a small shoal.

I could rehome them in a pond. Not ours. We had ponds when I was a kid and it's not a responsibility I want at the moment!

I think I am going to find a bigger tank.

Not sure how to tell DP. Perhaps I just sort it out... He probably wouldn't notice.

Thank you for your help.