Goldfish problem

[appleblossom]

My bloke's mother had a single fancy goldfish, about 2.5" in length not including fins, and about 2" in height, again not including fins, in a hexagonal tank which must hold about 25 - 30 litres. She insists on cleaning the filter sponge in tap water, never does water changes and keeps it in there with a pathetic internal filter and some mouldering plants....

This fish has lasted a lot longer than most of her others...yes she gets through a lot...
today she noticed it has a mark on one side which she thought was where it had scraped itsself on the gravel.

I had a look and there is a brown lumpy line about 1cm in length and 3mm in width on one side, it looks like a cut with a thick scab on...although i dont think goldfish get scabs but thats the best way I can describe it....

There is onlt gravel and plants in the tank with the filter on the back which has a long nozzel sticking out of it where bubbles are meant to come out to increase the oxygen in the water, although bubbles are a rarity...

Any ideas what this is?

I cant persuade her to get a bigger tank/get a nire suitable fish for this one or do water changes or stop cleaning the filter sponge in tap water, so what can I do to prolong the life of this fish, and possibly improve it if I can???

 

[The-Wolf]

That sounds like an infection of some kind
try this link
for a good diagnoise site. HTH

 

[Opcn]

Mabey you can put a small leak in the tank to prevent ny other fish from haveing th same fate. Its atought call I can't tell you wether its better to have the fish life a long and horrble life or a short and horrible life.

 

[ryan]

Could be a parasite or old wound, but in a tank that size with no water changes diseases will occur often and sadly this is how many goldfish meet their dimise.