Lund trolling motor plug question

I bought a new Lund 1400 Fury and when I went to plug in my new trolling motor to the receptacle it did not fit. Do I need a special plug or am I missing something? The receptacle on the Lund has two pins and a little triangle piece at the top. Any help would be appreciated.

Here is the right plug. Fits perfect. 

Turns out that one came with the boat and it was in the package that I received when I bought the boat. I am now good to go! What a way to learn a lesson!

I am using an after market Atwood. Maybe that is the issue. The motor is a 12 volt minnkota power drive.

Just buy a receptacle to match the plug on the trolling motor. Motor guide makes a standard plug and receptacle. I like the type you plug in and twist.

That looks like a standard receptacle. 

What kind of trolling motor do you have?