Many Fish Dead - help!

[halloween75]

It's not a huge mystery why but also doesn't make too much sense to me...and I'm not sure what to do now. I used Flatworm Exit last night (I have used it two other times with absolutely no problems) - I used slightly more than the recommended dose bc the other didn't fully work and I was told that would be ok. I had the tank pro cleaned for the first time on Sunday and he got out most of the worms but I figured for the rest I'd use Exit. Last night all seemed fine... I took out the carbon and after about 10 min when the started dying (flatworms) I put it back in. I took out as many dead ones as I could but still there were a lot there. This morning I came down to dead fish - blue chromis, yellow tang, hawkfish, dwarf lionfish (gills still moving but pretty much dead)...still alive is one chromis, comet, wrasse, and couldn't find Royal Gramma. I tested the water and all are fine except Nitrite at 0.5 and Nitrate at 80. Ammonia is 0. Problem is I won't be home for another 7-8 hours - is that really bad?? What do I do after taking out the fish...do I need to do another water change? Anything else? Very sad. Thanks!

[dc]

I would be water changing. I know the flatworms are toxic, sounds like you had a ton of them.

[Shagsbeard]

Water changes and cleaning... that's all you can really do at this point. Change your filter media as often as you can. Clean clean clean. Get the fish that have made it in a hospital tank until their usual tank is stable. A hospital tank isn't hard to set up, nor expensive. A food grade container the size of a trash can works great. Your hardware store is likely to have one. Read up on hospital tanks and get started on one.

In the future, QT everything you put in your tank, and it's likely that you'll never have this type of problem again. 4-6 weeks in QT is a bit stressful for both you and your fish, but it's a whole lot better than the work you have before you.