i just bought a green spoted puffer today at the pet store i work at i asked my boss if it would be a good idea to get him considering that i have many fish in my tank he said they would be fine but i was reading about them on the net and i read there tempermental and are fin-nippers

im afraid for my fish! he still is small i dont think he will try anything with 3 sharks in the tank but then again...IDK
what do you guys think will he hurt my fish
or no. feel free to ask 4 more info if you need it.
P.S. they seem to get along fine till now but what do you guys think