Common genetic deformity in man-made TSN and TSNxRTC. Peculiarly, I've never seen it in RTC.
Called duck-bill deformity, camel face, etc. These are rejects from farms that are dumped in the ornamental fish trade.
Severity varies a lot from specimen to specimen.
It won't change over time. Does not seem to affect the fish behavior or feeding much though, except mutations don't occur alone but in bunches. Longevity, health, size appear to also often be affected in a deleterious way.
It's not an RTC nose in that RTC snout is as straight as that of TSN, just shorter. The snout bones in this mutant are curved downward, not straight.