It may become necessary before moving specialist fish like our 26" mbu puffer.Because of the risks of puffing up in air if netted,3 months before the move I gradually got him used to me gently putting my hand under him and guiding him along.Given the damage he can inflict(did you see the pics of the hand bitten by a mbu recently)thats why I took 3 months of building trust.On the day of the move I guided him into a 48"x24" bag,lifted him into the new tank and he never flinched.Nearly broke my arm lifting him from 6ft up with the other hand on the steps though.