Big Problem! Need Help!!!!!!!!!!

[OnoIgotICH]

I have a 480 gallon... fowlr
ALL parameters are great...



8.4 - ph
0 - no2
0 - no3
0.5- nh3/4
Alk- 3
8 month old tank
SG- 1.021

3 yellow tangs
4 Diamond goby
2 clown wrasse
2 blue chin
1 blue face angel
2 blue velvet damsels
6 false percs

Just recently I've been encountering random fish deaths. My two goby died overnight as well as all damsels and percs.
Today my blueface has a VERY noticable pinch stomach, whereas yesterday he was GREAT, healthy and eating everything.
I had some people over for a party a few nights ago and it hasn't been the same.

My friend had a regal tang and purple dottyback, I tried putting his fish in my tank and they too had pinch stomach 3 hours into the tank and died suddenly (a day later).

What could be the issue ? Damsels dont die and my 8 month clown wrasse (who lived through ich and cloudy eye) died as well.

I noticed a few fish before they died would do somersaults and swim sideways as if they had bladder problems. Could this be a result of someone else tampering with the water ?

[Kannin]

poison... or electricity...

[lvpd186]

It sure sounds like something happened at the party. I would check your substrate for anything that might have been dropped in the tank and start doing some large water changes. If you haven't done so already I would also start running carbon and maybe some poly filters. Good luck! (I would also start asking the people who were at the party to see if they saw something, maybe you will be able to figure out what happened)

[01saleen]

Major water change, @ carbon is a must. Also, like Kannin said check the electricity, to see if any volts are leaching in to your water.