Lose of fins on Koi fish

Question
All my water levels are adequate I test them daily . But I have just bought a 75 gallon tank with 2 Koi fish included . After a week and a half the first fish starts lossing his fins and died . Now the second one is acting the same jumping out of the water and lossing the fins can you help me . Please .

Answer
Hi Cassie;

It sounds like something in the water. Fish try to jump out of it and their fins become deteriorated from waste toxins or even chemical contamination. Since the tank was just moved, it may be going through a break-in period as if it was new. If you haven't done so already, test levels of ammonia and nitrite. (Not nitrAte, it's different.)

Make a 25% water change to lower the concentration of whatever could be in there. Could a chemical, cleaner, spray room freshener, hand lotion, etc., have gotten into the tank? Were any new decorations added to it?

Let me know what you think.....

At Your Service;
Chris Robbins