UPDATE: Experimenting with the list playing on rank 5 to be able to have competitive basis.
Depending on situation you do not always need to keep quest from your starting mulligan.
Against aggro decks do not keep it. You will be not able to outpace them. Get Maelstrom Portal, Lightning Storm, and Lightning Bolt.
Against control try to keep Primalfin Totem, Mana Tide Totem. Call in the Finishers is also a good keep.
Megafin and ending the game
Remember that Megafin allow you to play flexible. In games where you are ahead, adding a 5 Mana 8/8 to the board in combination with the free Murlocs received can often devastate your opponents and win the game. Megafin brings you a HUGE value later in the game as you run out of cards. So it is often better to hold onto Megafin as you grind opponents down, providing a final burst of resources that they cannot answer.
Against control, it is best to hold back and extract as much value out of the board using things like Primalfin Totem and Flametongue Totem to force removal out of your opponent. Keep in mind that your opponent can have exact removal that counters yours entire board for 1 cast. So try to bait it before your final burst. The constant threat of Bloodlust is enough to make your opponent overreact most of the time. It is in these situations that Megafin truly shines, allowing you to refill your hand at a moments notice. As your opponent runs low on cards, you can start to add more minions to the board, or burst them with Bloodlust. But remember not to throw all your stuff hoping that your minions will survive next turn. Always keep some cards in your hand for your opponent not be able to read it. Let him guess what you still have and then finish him.
Sated Threshadon is an optional card. I like its body and sometimes 3 murlocs is just what you miss for quest. But you can also swap it for Eater of Secrets to counter mages Ice Block or Golakka Crawler/Hungry Crab.
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