i have one in my 29g biocube. this tank has MH lighting. the duncan is on the sand bed, low/medium flow. i target feed it with mysis, brine shrimp on friday because friday is junk food day at my house, and pretty much everything else i feed. i use a syringe and squirt it into the middle. i've had it for several months, started with 3 head and now has 7.
i don't have any recent pics but here it is under the actinics.
<a href="http://s6.photobucket.com/user/Ninapearl/media/duncan_zps5d383483.jpg.html" target="_blank"><img src="http://i6.photobucket.com/albums/y203/Ninapearl/duncan_zps5d383483.jpg" border="0" alt=" photo duncan_zps5d383483.jpg"/></a>
and right after being fed.
<a href="http://s6.photobucket.com/user/Ninapearl/media/duncan_zpsfebf3468.jpg.html" target="_blank"><img src="http://i6.photobucket.com/albums/y203/Ninapearl/duncan_zpsfebf3468.jpg" border="0" alt=" photo duncan_zpsfebf3468.jpg"/></a>