Compared to striped or white marlins and sailfish, black marlins are more solid than their blue counterparts. They have a shorter bill and a rounder and lower dorsal fin. Black marlin may be distinguished from all other marlin species by their rigid pectoral fins, which, especially from a weight of around {{convertcvt|150|lb68|kg|disp=fliplb}}, are unable to be pressed flat against their sides but can be tilted further backwards for reduced drag. {{citation needed|date=September 2020}} The maximum published length is {{Cvt|4.65|m|ftin}}, and the maximum weight is {{Cvt|750|kg|lb}}, possibly up to {{Cvt|900|kg|lb}}.<ref>{{cite web |title=Istiompax indica, Black marlin : fisheries, gamefish |url=https://www.fishbase.se/summary/217 |website=www.fishbase.se}}</ref><ref>{{cite book |last1=Flindt |first1=Rainer |title=Amazing Numbers in Biology |date=21 December 2006 |publisher=Springer Science & Business Media |isbn=978-3-540-30147-9 |pages=12 |url=https://books.google.co.in/books?id=9t7Tht1kf88C&newbks=1&newbks_redir=0&printsec=frontcover#v=onepage&q&f=false |language=en}}</ref>
