unknown crustacean

[Ron448]

so I've seen these little white crab looking things in my tank the past couple nights. they look like a mix of a sand crab and an amphipod and I've never seen them before. I've also already checked the hitchhiker guide from lionfishlair.com and they were not in it. hopefully someone knows what they are and can tell me if they are a problem. the video in the link shows it moving in the very beginning. the first time i watched it I missed it and i had to drag the navigator all the way to the beginning of the video. thanks in advanced for any help

Video: https://www.youtube.com/watch?v=bLRnWhEnpVA&feature=youtu.be

Here is the best picture i could get
<ahref="http://s79.photobucket.com/user/asolitt/media/IMG_2455_zpsfo1ltdow.jpg.html" target="_blank"><img src="http://i79.photobucket.com/albums/j150/asolitt/IMG_2455_zpsfo1ltdow.jpg" border="0" alt=" photo IMG_2455_zpsfo1ltdow.jpg"/></a>

same photo not so zoomed in
<ahref="http://s79.photobucket.com/user/asolitt/media/IMG_2455_zpsnbv1inot.jpg.html" target="_blank"><img src="http://i79.photobucket.com/albums/j150/asolitt/IMG_2455_zpsnbv1inot.jpg" border="0" alt=" photo IMG_2455_zpsnbv1inot.jpg"/></a>

 

[Calappidae]

Isopod?

 

[Ron448]

Unless it's a different kind of isopod I don't think it's an isopod. Isopods are on the hitchhiker guide and I've seen many in my tank already and this is different than all the other Isopods. Pretty much every time I've seen these things they have been on a coral and the Isopods have just been on the glass

 

[Ron448]

here are some pictures of it under a microscope
<a href="http://s79.photobucket.com/user/asolitt/media/IMG_2466_zps7lwxbfva.jpg.html" target="_blank"><img src="http://i79.photobucket.com/albums/j150/asolitt/IMG_2466_zps7lwxbfva.jpg" border="0" alt=" photo IMG_2466_zps7lwxbfva.jpg"/></a>
<a href="http://s79.photobucket.com/user/asolitt/media/IMG_2469_zpsxqgld8g5.jpg.html" target="_blank"><img src="http://i79.photobucket.com/albums/j150/asolitt/IMG_2469_zpsxqgld8g5.jpg" border="0" alt=" photo IMG_2469_zpsxqgld8g5.jpg"/></a>