Is there something wrong with my female shubunkin

I have two shubunkins in 20 G tank. I noticed that the female is rapidly opening her mouth and stands still in one corner of the tank. The male though is swimming naturally in the tank. Is there something wrong with my fish?

A fish that is not moving, is a sign of inpending problem. Unfortunately it's hard to learn what is the problem at this stage.

What you can do is to keep water prestine by doing more water change (50% twice a week for 2 weeks) and see if the situation improves.

I wouldn't recommend medication now until you can identify the problem. Hopefully the water change will solve it.

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