Originally Posted by mommyof3
The tank is 2.5 gallons she is the only fish in the tank, i do 50% water changes every 2 days temperature match with water comditiomers and check ph amd ammonia levels daily amd complete water change once every 2 weeks... readings r all within normal ranges.. did full water chamge this morning wn black lips were noticed
... she looks as though she has a black moustache
What are you using to test with and what are the exact readings? Test strips are known for being highly inaccurate.
A 2.5g tank is too small for her. What is happening, because goldfish have a huge waste output, is the ammonia is rising too high between water changes. Your never going to be able to get on top of it in a tank of that size with a goldfish in it. The ammonia is causing the black marks. They are burns.
The rule of stoking with goldfish is 20g for the first and 10g for each fish after that. So ideally she needs a 20g tank or larger.
What I'd suggest it twice daily 50-75% water changes and getting yourself a API liquid master test kit. She going to need a bigger tank ASAP.