Hi,

5 polar bear for fishing  how much reduced fishing time ?

Can i choose polar bear with "conqueror pack"  (item) : pet choise box tires 3 ?

Thanks

Reduced fishing time special doesn't stack.  Some other specials are like that too.  In some cases (all?) multiple pets of the same type cannot be taken out.

ok, and if i use: 

1 penguin, 1 bear polar, i parrot rare (boat swain) ?

It's the special that won't stack, regardless of what pet it comes form.

i thank you

In the case of polar bears, their weight limit increase talent will stack, so depending on what you're trying to do, it can make sense to have multiple of them out, but as Entropoid says, their special ability to reduce the auto-fishing time does not stack (and that special ability doesn't stack with any pet that has it). But even if it did, you'd be better off with pets like otters or marmots, because their talent is a life skill XP buff, which actually benefits you while fishing, whereas the polar bear's weight talent does not.

I suggest that you read these guides if you haven't:

https://grumpygreen.cricket/bdo-pet-guide/

https://www.blackdesertfoundry.com/pets-guide/