Please help---all my fish are dying...

well, today is not a good day for me at all. First off, I have a 55 gal, recently cycled tank (about 4 weeks ago.) Up until Tuesday, everything seemed perfect. My four fish (2 clowns, potters angel, bicolor angel) were getting along well, eating well, and basically living a healthy life. Suddenly on Tuesday, the bicolor stopped swimming around, and spent all of his time in the live rock. Then on yesterday he came out, swam around a bit, then suddenly died. Later on (last night), the potters angel started doing the exact same thing, and I found him dead this morning. Now my clowns aren't behaving normally either, and I'm afraid I'm going to lose them too.

Can anyone please tell me what the heck is going on?! By the way, my water chemistry is almost perfect, with 0's across the board and a slightly low ph (around 8.0-8.1) My salinity is normal, and my water temp is 79-80 degrees. I've been doing regular water changes (10 gal every 10-14 days) and I'm running a wet/dry filter with protein skimmer. As you can imagine, I'm very frustrated, especially considering I have no clue what is going on and how to remedy the situation. Any advice would be appreciated. Thanks.

Well, after a visit to my LFS (owned by a great guy who really knows his stuff), he is 90% sure that Windex is what killed my fish....yes, Windex. After testing my water and examining the dead fish, we both noticed that they looked great, and showed no sign of disease whatsoever (such as ich, red lines, etc). Given this and the fact that my fish died so suddenly, along with the fact that I have indeed used Windex to clean my glass, again he's almost positive that this is the culprit. Well, I never realized that even the slightest amount of windex (such as mist from an overspray) can kill off the entire tank. He also said that windex is attracted to water, so even windex sprayed near the tank will often find its way into the water.

He went on to tell me that in his 30+ years of running his store, along with all he's read over the years, toxins like Windex, soap, cologne/perfume, etc. are most often the cause of death of fish in cases like mine (sudden death with no signs of disease.) So, hopefully this indeed is the case, in which I learned a valuable lesson the hard way. I just wish I knew of of this beforehand. Oh well.