Hi everyone Thanks for your help in advance. Should I be concerned? See photo. Few info beforehand: our prime from seachem was sold to us expired, so our fish kept dying after 1 day. Our parameters and temperature were fine, but it seems that the prime was causing the death after having a conversation with an ichthyologist. He suggested a 50% water change and add some aquarium salt. After 3 days it should've been fine. Let me know what you think, or what other info you need from me.