one of my fish has some kind of dirt on it. What is it and how to treat it?
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Answer: Don't anything with it yourself take it to a fish doctor
Explanation:
could be very contagious and or deadly
Answer:
those are called black spots since you have a goldfish it will happen but they should go away because that is what happen to my fish and he looked just like that. So make sure you clean the tank and keep an eye on it.
Explanation: