Hi agk, Welcome to Fish Lore,

I see you have another thread about your angels, I'm sorry you're fish are not feeling well.
How many gallons is your tank?
Are you testing your water? If so with what (the strips aren't accurate) and what are your readings?
I see you don't know about the nitrogen cycle, please take the time to read this:
http://www.fishlore.com/NitrogenCycle.htm
A couple things I could suggest, I'd do a water change now, especially with your angels not feeling well also.
Your fish and turtle(?) are not compatible, you should consider separating them.
I hope some of this helps.
Good luck with your tank.