Well, the reason I wrote "suspicously" is that there isn't a surefire way to tell just from the video you posted - as you know, the most exact ways to identfiy fish we tend to employ usually require high-resolution and well focused pictures. (E.g lateral line scale counts - pure goldfish have 28-30, carp have 35-40). What's more is that in situations like the one you described, interbreeding is often so rampant that there is not only F1 Hybrids (in this case Carassius Auratus x Cyprinus Carpio) but also a plethora of F2 and F3 which end up being something like (Carassius Auratus x Cyprinus Carpio) x Carassius Auratus. I used to go fishing in a private lake stocked with carp and goldfish and you'd find hybrids of all sorts but also pure goldfish up to a whopping 16".
What made me suspect hybrid, though, was that;
1. The body is very deep behind the pelvic fins. Pure goldfish are often quite deep bodied up to the pelvic fins (either for ornamental reasons or just because they are well fed) but the body tapers down more towards the tail.
2. The mouth, while you report it does not contain visual barbels, does not look like a pure goldfish's (they have thinner lips and the mouth is more terminally positioned on the head).
3. The biggest clue for me is the positioning of the eye. In pure goldfish it is quite a lot nearer to the end of the head and the mouth than in koi and hybrids.
Again, without high res pics and a lateral line scale count this is all just stabbing at the dark and I might well be on the wrong track here. Just my two cents based on the video.
What made me suspect hybrid, though, was that;
1. The body is very deep behind the pelvic fins. Pure goldfish are often quite deep bodied up to the pelvic fins (either for ornamental reasons or just because they are well fed) but the body tapers down more towards the tail.
2. The mouth, while you report it does not contain visual barbels, does not look like a pure goldfish's (they have thinner lips and the mouth is more terminally positioned on the head).
3. The biggest clue for me is the positioning of the eye. In pure goldfish it is quite a lot nearer to the end of the head and the mouth than in koi and hybrids.
Again, without high res pics and a lateral line scale count this is all just stabbing at the dark and I might well be on the wrong track here. Just my two cents based on the video.
