Let me start off by saying, that my favorite color is Blue.  When it came time for me to think about Heraldry for my SCA Persona, Giovanni, I decided pretty early on, that it would probably include the color blue.  I also wanted the over all design to be as simple as possible.  I also like aquatic things, and thought that perhaps a merperson might be a good match for the not very evolved conection of my persona to the Baronial navy, in case it did grow.  In researching, I learned that there were several mer people in heraldry already, and on blue backgrounds.  White is the most logical color for a Mer person, especially on a blue field and in hearaldry, White=Silver=A sort of Silvery Grey, and all the others had them already.  You need two good points of difference (or at least it was only two at the time, not sure now), so I went for a winged merman as my first attempt.  It passed, but was very close to someone else's device.  They agreed that it could stand with one point of difference, and thus was born my device.  Several years later I got an award of arms for service, and was made a Lord, with Arms.

Here is the device I've worn on my belt for several years.  I'm the artist, for good or bad, of this rendition.  Click the progressivly larger versions till you tire or your browser croaks, or you run out of larger versions...

Click the image above for a larger view.