fISH dying out

Question
My stickcatfish, harlequins, khuli loaches, balloon Mollies, golden loaches, black Mollies have all died out. my gouramis, discus, rummy nose tetra, angels, dojo loach, bala sharks and corydoras all seem fine. I tested the water in the tank and came up with the following results:

ph: 6.0
High ph: 7.4
Ammonia: 4
Nitrate: 0
Nitrite: 0

I do not know if the ammonia is to high?
Could you help me out?

Thanks

Answer
Hi Peter
Yep, ammonia is way too high.  Sounds like it's a new tank I'm guessing?  If so, it's going through what's called the cycle process.  Here's a link, it's the first article, explains the cycle process:

http://freshaquarium.about.com/od/startupcycle/Step_5_The_Cycle.htm

All new tanks go through it.  Also, what size is your tank?  
Read through that link/article, and let me know if you have any questions on it.  Let me know on the tank size too and we'll take it from there.

Christy