Hi,

I used to feed my two discus - Hikari Discus Bio-Gold. Today I tried a different brand and gave them New Life Spectrum Discus Formula. After they ate the pellets, the eyes of one of the discus turned completely black. After an hour they got lighter and seem to be getting back to normal. This didn't use to happen when I fed them Hikari Discus Bio Gold.

Is this something I should worry about?

thanks