It isn't that surprising
There's no use of having bigger teeth without a higher bite force
So in order to have a higher bite force fish need support to the muscles and also for the teeth
That's why most of the fish with bigger teeth have strong muscular jaws and teeth connected straight to their skull which not only help to deliver a powerful bite it also helps to absorb the impact better than a extendable jaw since cartilage based jaws could be damaged on higher impacts
They are known as active predators or open water predators
Ex
Tiger fish, Piranhas
But for fish that use more extendable jaws need more mobility and that's why they have jaws that are mostly made out of cartilage which are more flexible than bones
And their teeth are smaller to have a better grip of their pray
If they had bigger teeth it's just gonna be more of a disadvantage because they don't have the power to deliver a bite strong enough for those teeth do some damage
They are known as ambush predators
Ex
most predatory freshwater fish species
But for few species of fish such as sharks this doesn't apply since their whole endoskeleton is made out of cartilage while being able to deliver a very powerful bite
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