Definitely enjoying this discussion. Seeing in person is always better than looking at pics but this is what my eyes see (from pics) - some Chad's don't look like other Chad's, some turkana don't look like other turkana infact I couldnt say which one is better looking.
So big question for me is why are turkana Soo much more expensive ?
That's the real question there. I would think it just goes down to supply and demand. Water bodies in Chad are much more accessible than Lake Turkana. So lower supply but higher / same demand as Chad = higher pricepoint. Doesn't help that any bichir from Turkana carries a mythical element to it which attracts buyers and allows sellers to tag them with a higher price.
Example would be a turkana sen v a regular WC sen. The price different is at least 4x.