Use Underbelly Anglers on themselves for the huge value or with Sludge Slurper for normal value, which can be intensified with Hagatha the Witch. 

Don't have Swampqueen Hagatha but you can replace something for it (Defender of Argus is usually the weaker/harder card to use).

You can test other Overload cards (I like Lava Burst but it's far from essencial).

Aside from this, the deck usually plays like Control Shaman. There is room to improve the deck, though.