Crawdaunt maybe have more recistances (Water Dark) but more weaknesses like Fighting type and Bug. But it´s the most easiest way to get. But it doesn´t learn so good Dark moves but good Attack moves that match it´s Attack stats. And if you have Shell Armor then you get Critical Resist or Hyper Cutter that doesn´t let you get your Attack lowered. And if we talk about Gorebyss and Huntail that you most trade for I would reccomend Gorebyss coz of it´s Sp.Atk. If you let Clamperl learn Iron Defense then you get a though Wall Tanker or you learn it Amnesia that let it be more defensive against Electric and Grass moves.
So I would reccomend Gorebyss with this moveset
Amnesia/Iron Defense (Mostly Amnesia)
Source Experience when I played it