Mulligans
General Mulligans
You want to start the game like any other aggro decks, you just flood the board with murlocs while freezing your opponent's face and minions. With Ice Breaker you can clear minions quite easily, so taunts should not be a problem. Around turn 4, you want to play Gentle Megasaur to adapt your murlocs and win.
Aggro Mulligans
Against aggro you keep MaelstromPortal for obvious reasons, and your freeze stuff to clear and slow them down as much as possible. Finja is very good for turning the game around.
Control Mulligans
Against control it is possible that you can't win with the early game, so Moorabi is included. He helps you to keep your hand filled with minions and keep pressure on your opponent. He is not enough in itself to win the game, but 3-4 frozen crushers should be.
This is an aggro deck with murlocs and freeze. If you can’t win the game early, Moorabi
loads your hand with Frozen Crushers or other freezed minions and helps you to finish against more control oriented decks. Deck is in testing phase, so please comment if you have ideas how to improve it. I used it around from rank 14 up to 9.