Harbringer of death?

Ok...so why do my fish keep dying? I just got this one 10 days ago....and now he's almost ready to go back to the store so I can collect on that 15 day money back guarentee. I think it's something with the tank, so on the plus side I'll get a free water test. On the not-plus side, I'll be short a fish, and they probably won't let me replace him today. That will be an odd number...9!! That's no good! oh well....maybe next week I can get another fish and have 10 again...

Update: Ph level was WAY too high. So, we add Ph Down a few drops at a time, and I should be able to add fish next weekend. I was gonna suck out the tank, but now i think I'll wait until Wednesday, and add the amquel and the ph down and hope for the best. Sad that I lost a beautiful fish, but I'm glad I can fix the water.