Dark Greeny Blue Fur On Rocks

[Pidgecbr600rr]

There is a dark greeny blue fir developing on top of my rocks, approx 1mm long now, none of the fish seem interested in eating it, just wondering what it could be and if its harmful or not? If it is Algae i thought platy's and cory's would eat it? Also i thought algae was definite green or are there diff varieties?

Thanks

Paul

 

[Bryan1957]

PidgeCBR600rr,
It sounds like alge. There are several types of alge; green, blue/green, brown (tan), and black. Some fish will eat certain kinds of alge and not other kinds. My platties and swordtails will pick at green alge and not the black type. My mollies will eat the black alge but leave the rest alone.
HTH
Bryan