Was browsing to identify a species on their site and noticed achilles tangs are "EXPERT ONLY" but I am not sure why. Is there something special about them vs. other tangs? Never had one myself, and they don't mention any difficulty in their description. The whitecheek hybrid is also marked the same so I don't think it's a typo.
Link: https://www.liveaquaria.com/product/prod_display.cfm?c=15+43+325&pcatid=325
Link: https://www.liveaquaria.com/product/prod_display.cfm?c=15+43+325&pcatid=325