Very red gills

[~nessy~]

the fish in my fish tank seem to have very inflamed gills i dont know what the sats are as of yet but i would like to know what is wrong wiht them any answers would be appreciated

 

[WILDER]

Tank size how many gallons, which fish and how many, red gills can be gill parasites or bad water quality, for now I would do a water change, are they flicking and rubbing against objects.