I had to do something similar back in the beginning of Feb with one of my 55gs thanks to a disgusting leech infestation.
Ughh -- how did that happen? Did you lose fish? I suppose you can understand how I feel then...
Everything went in the trash except the tank & the filter housings.
That's precisely what we have done with the 60 gallon...we're even starting over with the filter media, from scratch.
My husband & I carried the tank outside in the dead of winter & I wiped everything down with bleach, soaked the filter housings in bucket of bleach water & rinsed the heck out of everything with the garden hose. And started all over from scratch.
So, I assume you lost all fish in that crash?
For whatever reason, the 60 gallon is simply too heavy for us to pick up and carry outside or to a bathtub -- we have to find a way to make this work at the location it's in, on its stand. When you say "wiped everything down with bleach," how did you do this -- just a cloth dipped in a mixture of bleach and water?
From what your describing, it sounds like there were more issues happening in your tank than just an infection.
Because of the filthy substrate and slime that is coating every surface now?
Here is my theory about what happened, jlk, and your input in terms of analyzing that would be most appreciated -- I think our substrate, which hadn't been vaccumed maybe for two times in the two years we had the tank, got so accumulated with bacteria and raw filth that it was just waiting to attach to a living thing that had an open wound of some kind. When our aggressive Red Cap nipped and attacked the two others, this opened up the wounds, which allowed the bacteria to attach itself and ultimately kill them.
Is this remotely possible?
If your going to restart this tank, switch the substrate from gravel to pool filter sand (very inexpensive). Then you wont have issues with filth & waste accumulating& building up in the gravel.
We were thinking of the colorless "natural" rock/gravel substrate you see in the "natural" tank setups, but the amount for our tank becomes VERY expensive. I have never thought of pool filter sand -- are you sure this would be okay with goldfish and the intake pipes of the HOB filters? I've read horror stories about people's filters getting killed by sand that would be sucked into them...
Your going to have to get another siphon-type setup so you will be able to suck out any debris that collects & do water changes regularly. There really isnt a way to avoid this with a 60g tank- if you dont, your going to encounter the same issues again in the future.
We realize that and talked about this last night...
How many water changes are necessary, truly, on a goldfish tank? Can we get by with a monthly 50%? And do a gravel vac with every one?
Adding 2 more fancies to the 10g was not the best idea. The oranda already has aggression issues. In this small of tank, the issues are going to compounded to the nth degree. I honestly would take them back until you are able to figure out the housing situation for everybody. I would wait on purchasing anymore fish until everything is straightened out. Obviously, you can make your own decisions on this matter but this is my suggestion for now.
I totally understand -- we just wanted to get a couple of mates for the Red Cap because he looked miserable in there without other fish. Yes, he is seemingly going after these fish too, yet it doesn't seem to be as bad as in our 60 gallon.
We absolutely do not plan on adding any fish to any other tank at any time soon -- if we get the 60 up and running, I just want a place for our Moor to go back to because she's miserable in the two gallon setup...