urgent!!! colors bleached?

Hi, thank you all in advance. I need a little insight. I just got back from vacation since wednesday, and left the care of my 20gallon in the hands of my brother after very thorough instructions. I came back to see my favorite blue spotted puffer that i love very much looking in very poor health, his colors seem off, about half is bleached/looking. he seems to be swimming alright, i cant see any infections as far as fungus/parasites go. his colors look timid. I proceeded to see my three stripe damsel extremely grey and not his usual black and also unhealthy looking. I have a yellowtail that is in the same boat and does not look healthy at all. However, my anemone is in perfect condition, no bleaching at all. The oddest part, is the only other fish I have is a maroon clown and it looks absolutely perfectly healthy, color is vivid and he is swimming/eating. can anyone help? This is an emergency as I would hate to lose these very loved fish =(

 

Get some airflow under the hood and around the tank in case it has to do with oxygen depletion. Test SG, pH, ammonia in that order.

 

Are they eating?
I'm thinking around the lines of O2 depletion as well.
But also, what about top off water? Did he top off while u were gone? If so, with what water, Filtered/RO/DI water. I've seen this happen with traces of chlorine in the water.

 

He did top offs, but only once and it was with a purchased gallon of distilled water (same company ive been using for a couple years). My ammonia is 0 and nitrates are low, my sg is 1.023. I live in the country and chlorine isnt present (own well) so that shouldnt be the issue

 

they are not eating. lights were off since yesterday morning (skipped cycle) which amounts to about 30 hours of darkness. I have a 55-75g HOB filter with a 3 strip t5ho 1 acintic 1 10k, and one 50/50


clown eats fine, I have the two damsels and puffer in my QT right now. thats on a seperate system with just cleaners and has perfect parameters.

 

So, which is it, well water or distilled?

Also, did you do a pH test?

With the long off cycle, I'm leaning more towards O2 depletion. You can check O2 depletion (very) indirectly with a pH test.

 

PH is 8.1-8.2ish.

 

Have the lights been off in the tank since you got back? Not on since?

If so, you may want to turn the lights on and let them stay one for about 10 minutes, then check your fish. Fish camouflage themselves when they sleep.

 

I have to agree here. Your fish would never react as they usually do when in darkness.