How did you store the fish?
On ice in a cooler, w/ cold packs in a cooler, or in bag in your trunk w/out aything?
Fish losing colors happens quickly depending on how its been store. Many times fish gets reddish on the side it lays - blood settles - no big deal. If fish as blotchy red sores/spots - I wouldn't eat it.
If it looked "normal" when it came out of the water then its probably OK to eat. I typically remove the innards/guts and be sure to tear out the gills - let is bleed out. Rinse out fish again in water to remove blood. Seems to help taste IMHO.
Lots of people dislike Bluefish, but if you bleed them out and keep them in ice it makes a world of difference. Removing the dark meat along the lateral line also helps w/ flavor.