Inspect the fins, do they look ragged? How big/old are the angels and how long have you had them? It is not normal for an angelfish to get stuck in plants even if they are plastic ones. It probably had something wrong with it.
It will also help to tell us :
What size tank?
How long has it been set up?
What other fish are in there?
What filter are you using?
Do you have a heater?
Have you seen any aggression between inhabitants?
How often do you do a water change and how much?
When was the last time you did a water change?
What is your water source? (City or well)
Did you use a declorinator (if city supply water)
If the fish is new did you quarantine it?
I see that you tested all parameters at 0....the nitrate should be higher if the tank is cycled, how old is your test kit?
With some more info we can probalby help you nail down the problem.
