Mark, Yeah, I always use loads of references, especially photos and videos of underwater habitats and fish, but on rare occasions I have even used a freshly killed dead fish when I had to get the image 100% precisely right and I could not find a reference that provided the info I needed.
Don't worry though, I've never killed a barbel for this, just an occasional perch, jack pike or bass, then afterwards, they were cooked or used as bait.