replaced filter cartridge

[Humanis1993]

I replaced the old cartrige with a new one but I fotgot to wash it off first. but now the gills on several of my fish have turned red. Their movement is regular I also did a PWC and their gills are still that red color. What should I do?

 

[HUKIT]

Have you checked your water parameters since then. Red gills is a sign of ammonia burn, it's possible you threw your tank into a mini-cycle. Let us know your water levels and how long the tank has been set up.