School Fish Help

[liz2]

I am not very good with goldfish. We have one in our classroom..he is in a really big tank with own filter....lost one about 3 weeks ago I think he had TB reading on here. Anyway no one fed the remaining one last week and he has developed black tinge round his gills and on his tail. Looks like a discolouration or could it be stress as he is by himself?

Cant test water or anything but any ideas would be welcome?

 

[LucyHurst]

Black appearing is usually a sign of ammonia burn, there might have been an ammonia spike or still is (black is the sign of healing, like a scab on a human).

 

[liz2]

do I need to change the water or anything then?

 

[ron1]

what's an ammonia spike?

 

[WILDER]

I would preform a water change just to be on the safe side while your school or you get the water tested.

 

[LucyHurst]

what's an ammonia spike?

Levels of ammonia are supposed to be 0ppm, so no ammonia in the water as its toxic to fish, so when you get a level (not really sure how high it would have to be to be called a spike?) its not good, and can make fish ill/burn them etc..

Liz, do you know how many gallons (US or UK) the tank holds and how many gallons per hour the filter pumps?