Fish scales imply troubles, memories, past, etc. that you want to throw away. Or a burden.
Having fish scales in your mouth may imply that you think you have concealed a lot of bad things, and you will feel at ease only if you tell them. In addition, it may be that you are dissatisfied with some parts of your past and hope to be relieved and released through talking.
It is recommended that you analyze the dark spots in your heart where you are often anxious. If you need to talk to others, you can find the right person to talk to, so that you can release the pressure and move forward better.