Dead fish - ick?

Question
I have a 65 gallon tank that's been established for years.  Haven't had any problems since the initial set up and have had some of the same fish for over 3 years.  All were very healthy and big.  Then I bought a couple of new, small fish and they died right away.  Then my clown loach got ick and I started treating the tank with Quick Cure.  After 4-5 days, the spots seemed to be disappearing.  Then, a couple of days ago the loach died.  Today I came home to find the rest of the fish dead.  No idea what happened as they did not have signs of ick.  Do I need to completely empty / clean my tank?  Has some disease taken over?  Any help would be appreciated!
Thanks.

Answer
Hi Susan
I know with clown loaches, they're very sensitive to a lot of the ich meds out there.  Being scaleless fish, the medicine can actuallly burn them.  Not sure what other fish you have in the tank, but the same thing with tetras, catfish, and other scaleless fish.  That may be the problem there.

Do you know what your water parameters are?  Ammonia, nitrite, and nitrate?  I'm wondering if maybe your tank was suffering from "old tank syndrome", basically the nitrates get high, and the fish adjust to it slowly.  Everything appears fine, then you add a few more fish to the tank and they instantly die for no apparant reason.  That's usually the cause-the old tank syndrome.  

Ich is always present in fish tanks, it's when fish get stressed for some reason or other that it "comes out".  I'm wondering if the new fish maybe added to the bioload, and caused an ammonia spike possibly?

I would say no to breaking down the tank completely.  I really think it was one of the problems I mentioned above.  You added new fish, they died immediately, other current fish-some get ich, you add meds, they all die.  

I would add some carbon to your filter to remove all the meds remaining in the tank.  If you don't have a water test kit to test those 3 things I mentioned, pick one up.  Do a 50% water change, and be sure to vacuum the gravel/substrate really good.  If there's no fish in the tank, go ahead and crank the heat up to about 86 F.  That'll help kill off some of the ich as well.  Just wait at least a week or so before adding any new fish, and just do it slowly.  

Hope that helps!  If you have any more questions, please ask!

Christy