Strange black bug in my tank

[Secret00023]

There is this strange black bug in our fresh water tank, well I think it's a bug. It's kind of flat and has little legs, hard to see in the pics. I'm worried it might not be good for the fish. Has anyone ever seen this? Does anyone know what it is? Any help would be appreciated.

 

[ADsnail]

Could be a water mite? They like algae. My knowledge beyond that is limited. I've heard everything from "dose 'em with chemicals" to "I left them alone for a month and their colony crashed". Sorry I can't be of more help.