Chromis - erratic swimming

[rower4fish]

I had a Chromis die about a month ago, erratic swimming, head popping above the water. Then the other one started swimming with his mouth locked open, just like the one above. Then the mouth would only lock open like that when eating. Then only with small particles in the water. Then seemed to quit almost altogether. Finally, yesterday he started swimming erratically like the one that died. He is still alive, but i have him in a net. Sometimes he sits quietly, sometimes he thrashes, sometimes he swims upside down, sometimes he looks like he has passed away

Any recommendations?

 

[Humblefish]

Any signs of Uronema (photo below)? I also have had chromis die this way and I suspected cyanide poisoning.

 

[twilliard]

Chromis are so unsuspecting with condition. One day good the next, odd.
What is the diet like for your chromis? I have noticed through the years that my schools depend on a wide mixed diet, constantly. If I do not switch up the diet they will perish quickly. Also they have to eat all the time.