Gosh Jonathan, sorry to hear that.
I hope your remaining clown hangs in there. Are the white spots ich? If so, you might want to pull your clown out (I'm assuming he is the only remaining fish you have) and put him in a
QT and wait at least 6 weeks until the ich cycles. If there is nothing in your
DT to support them, they will cycle out and die. I can't remember exactly the cycle span time frame as it could possibly be a much longer time than I am stating. I'm sure someone else can chime in on it as this has been discussed before somewhere else in a post. But as long as you have something in your tank, you run a high risk of keeping an ich parasite at some growth stage in there. Sort of reminds me of the life stages of a flea.
They live in the water column. One day you see one spot on a fish and then the next they're covered and a blink of an eye, Game Over. It happens that quick.
But always remember..... "You have to go through the bad to get to all the GOOD and it makes it all the more special. Chin up, we're cheering for you!
