Black gill on gold fish

[El_diablo]

Hi guys, a friend of mine has a gold fish that he's had for around 5 years now that now he's a bit concerned about as he has a black lining along 1 of his gills. The guy at the lfs has told him its ammonia poisoning but then sold him some nutrafin cycle for some reason? (I'm almost sure that's wt lfs sell u when ur setting a new tank up then they tell u that cycling ur tank takes 3 days that we all know is a load of rubbish) I'm going back there this afternoon to test his water parameters so il know then if there's any ammonia in his water but he does weekly pwc's so I don't c why there should b any ammonia in his water now? Sorry about the long winded post but if anybody can help we'd b grateful

 

[jlk]

Some more information will definitely help! The water parameters (ammonia, nitrite, nitrate & ph), the size of the tank, the filtration (gph), amount (%) & frequency of water changes and any tankmates are all things we will need to know in order to be able to help. In addition, does he change the filters on a monthly/regular basis? This would throw the tank back into a cycle & result in ammonia being present. Black on gills (or any part of the body/fins) is usually a sign of ammonia burns but more information is needed.

 

[jlk]

Forgot- what type of goldfish is he and any tankmates & how big are they? Thanks!

 

[El_diablo]

He's a common goldie who is in a 20g with a black moor and another common goldie, now he knows his tank isn't big enough but trust me it's better than the 2g bowl the lfs sold them in! The filter is jus the stock filter that came with the 20g tank he's looking at buying a bigger filter now, he also knows now to seed the new filter before completely replacing the old filter so all the beneficial bacteria isn't lost. Iv jus tested his water with a nutrafin liquid test kit and it's bin a week since his last pwc and the parameters are ammo 0 - nitRATe 20 - nitRITe 0 - ph 7

 

[El_diablo]

Sorry he changes about 20% a week when he does a pwc but last week changed around 75% because of the black on his goldies gill

 

[jlk]

Thanks! Yes, as you are aware, theres some serious stocking issues here. Realistically, the only fish that should be in this tank is the moor. The best I can recommend is to continue with weekly or even bi-weekly big water changes & consider rehoming the commons to a pond (or a very large tank) where they belong. Its very possible there was a spike of ammonia because the bioload of this tank is overwhelming. The blackness on the gills should heal on its own with healthy water but it will take some time. If he is adding another filter, I would just add it & run both filters to increase the filtration on this tank permanently. Please do not hesitate to ask any questions!

 

[El_diablo]

Great stuff thanks for the advice I shall pass it on