Today I woke up to a major tank crash my dotty back dead and my 2 clownfish hardly even moving. I quickly took the clowns out and put them in a QT tank with an airstone and filter. I tested my nitrate/nitrite it was off the charts! The one clown died after 5 hours of being found. The spike happened sometime over night between 1am-10am. My tank is established and is a full reef tank. I've had a BTA in there for about a year. Last night I fed it a sliver side and found it rotting in the tank, also I fed my corals last night. I did a few water changes and lowered the nitrate/nitrite levels by about half. Still high but going down, have a fire shrimp and watchmen goby who seem fine. I am really worried about my one clown he's been in QT for 9 hours and has improved a bit, when he was first found he was laying on his side and could hardly swim, over the first hour he was able to upright himself and swim a but on the bottom. After 2 hours could swim to the top of the tank and has moved around quite a bit. Has anyone had a fish survive such a huge crash? She is a very strong and hardy fish has made it through an outbreak of marine ick and brooklynella. Any advice would be helpful aside from keeping my fingers crossed is there any chance my fish will make it?