Like it says all of my catfish died started about 2 weeks ago and now they are all dead, but my koi that are in the same tank look and feel fine and frisky. All the numbers are great and nothing has changed .It has started to get a little hotter here (NC)  but the tank sits half way in the ground so water temp is around 78-80 .  Only chemical used were Hi-yield Thuricide and that was awhile back.…