Fish and coral problems

[cinswan1]

I hope someone can help. I have had my 135 saltwater aquarium for 3 years now. I noticed white spots on my coral beauty so I put her in a quarantine tank. She died later that day. The next day I came home to find my angel and pajama cardinal and one clown dead which none had any signs of spots. I removed the rest of the fish and started treating for ich but my yellow tang looks very skinny now and you can see his bones. also my frogspawn and hammer started dying off. The other corals seem fine for now. What could be happening? Please help!

 

[Sniperhank]

What are your current parameters? It sounds like things have been going downhill for some time. I'd suspect issues with parameters if you are seeing ich, skinny fish, and coral dying off.
What is your water change regiment?