fish are to damn strange to figure out. when i first started fishkeeping years ago i thought these things dont care if i slam them on concrete but after years of keeping i kind of agree with you. they know something is going on and may perhaps be in mourning or very sad. its hard to say. even the top scientists havent figured it out.
FIsh must have feelings, IMO every living creature does.
I would have to say it must be something in the water, something you didn't test for.
If its not effecting the parents, I can't see it endangering them.
I think I may have figured out what might have killed the fry. A day before they all died I added tetra algae control because I had some algae starting to form. I didn't overdose the algae control but that may have had some affect on the fry. The male and female dovii are still "sulking" in their seperate corners of the tank and both their colors look very dull, if that makes sense and I am starting to worry about their health as well. I just performed another 2o-30% water change but nothing seems to help. Should I add some aquarium salt since I haven't done that yet? I feel like I'm out of my element at this point.