Ok I have a 40gal tank. My sons friend gave me this came and set it up it has 2 bluegills/sunfish 1 is 4 years old 1 is 2,i have i small albino cat, i small placo. Dont know how old they are was given to me. I also added a bala shark which iam told was wrong.got it. Before i had bought a goldfish/koi. and another larger placo. After that my 2 sunfish have gotten a cottony filmy grayish whitish coat they are not eating and really lathargic. 2 year old looks like hes swimming sideways. I have changed the subturate to rocks instead of gravel thought that would help get rid of whatever this is. Have treated with rid-rich was told to stop. I have taken the koi and placo out cuz they died. I clean the tank everyday and do up to 50% water change also. My nitrates i have gotten down with prime and water changes. My ph is 7.5 nitates were 80 and nitrites 0 . I use well water. Also have a aqueon 50/75 I have also added live plants to help lower nitrates. What i would like to know is what treatment do i give them as i get no response. Have been asking since friday and even upgraded my staus on here. Can anyone PLEASE tell me what to do ? Aqarium salt and heat ?. Please there not doing well. Iam new to this hobby : )