Nice! I thought it may be an s. mertensi, but it's clearly not. Best of luck with your Hadonni!
LOL... I thought you might be thinking, since the oral disk does look a lot like that of a mertensii. However, take a look at the first photo again, and check out the reflection on the side wall of the tank -- no verrucae. :dance:
What would the foot look like if it was a mertensi?
This is the same nem in my tank, hope you don't mind me posting it.
<a href="http://s104.photobucket.com/user/lenny732/media/Mobile%20Uploads/image_7.jpg.html" target="_blank"><img src="http://i104.photobucket.com/albums/m178/lenny732/Mobile%20Uploads/image_7.jpg" border="0" alt=" photo image_7.jpg"/></a>