I don't think so there is alot of fighters that don't but are look at Oscar I don't think he looks tough but he is
Manny is not a tough looking dude , even when he attempts to make those intimidating poses, its still hard to take him seriously . then when he gets into the ring , a f*ckin serial killer comes out swinging with bad intentions .
There's no precise way to tell just by looks, but tougher features like a squared chin and deep voice are indications of higher testosterone. So if you placed bets on a hundred fights and bet on the guy with a deeper voice and broader chin to win fights - then you'd probably net out slightly better than if you always bet on the guy with a higher voice and dainty chin. But then again, there's too many other factors to consider, that in many examples, the opposite will be true.
I also knew this salvodorian kid back in high school . This kid was one of the softest lookin people i ever saw in my life . Black kids used to "try" to bully him all the time cause of his thick accent . What they didnt know about this kid was that he was a brown belt in shotokan karate and have been training ever since he was 10 . Poor kid name Urick tried to swing at him and it was all downhill after that . Long story short , we all witness a beating and urick ended up looking like Balboa when he first fought Apollo . 3 or 4 other black kids try to take him on thinking they will do different because like they say " Im from the hood " or " i got hand skills " From what i heard because i did not witness those other fights , They all got beaten down with EASE . That kid transfered after his freshman year . I never saw him again , i would like to know hows life treating him though , in a way i always felt bad for the kid , it was always drama with him .
Great example of this in action would be Calzageh vs Lacy One built like Hercules, the other skinny and pale