Is your tank too small? A tank that is too small will make the fish nervous, swim around, and easily cause the fish to fight. Your fish’s injuries should be caused by collisions and fights~
Isolate the injured fish first. Add a little salt and xanthate to the water. It will get better in about three days. You must isolate it quickly, otherwise the smell of the injured fish will make the fish fight more fiercely~
Yours is a Feng Shui fish. If the tank is too small, if conditions permit, change to a larger tank. If not, you can also raise five fish~
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Add until the water turns light yellow. Generally, if you have a wound, you need to add xanthate. The wound will heal faster ~ add salt It's getting better little by little, about one spoonful for five to four servings~