Don't be so fussy mate. It doesn't matter AT ALL but some folk actually have the cheek to correct you if your opinion doesn't fit theirs!
It's far more entertaining to call everything a cod — which they ARE, just the same as a puppy is a dog — and sit back and watch all the anal retentives getting in a tizz.
Then if you catch a double, call it "just a codling" and everyone will be really impressed!