Normal isn't accurate enough. Do you know the exact number for Ammonia, nitrites? Do use strips? Strips are useless. You need a liquid test kit if you dont have it.
Do you use water conditioner to remove heavy metals?
How are you fish behaving? (At the surface, laying on the bottom, what?)
Actually I may have it figured out. Looking at that plant... What kind is it?
If you bought it at a pet store, it may not be an aquatic plant... so plant rots, produces ammonia.
I would remove the dying plants to a bucket, and still do your water changes.
Last edited by redchigh; 08-21-2010 at 12:51 PM..