whats this black stuff???(pic)

hi
have noticed one of our plants has developed some 'black stuff' on its leaves.(see attatched pic) it doesnt rub off easily. is it an algae of some sort??? we dont want this plant to die - our tiger barbs use it as their 'bedroom' they always park under its leaves at lights out time. sorry i dont know its name, its been in the tank for about 4 months.
anyone know??? we have a planted 37 uk gal but no co2 system. i know we really need one to get our plants looking really good but ive after a year just got to grips with keeping a community tank healthy & co2 all sounds a bit complicated .
thanks

you got black alge, its the worst form of it and really hard to get rid off, the only way i got rid of mine was taking out everything that had it on it. i asked a couple of lfs and they said the same thing.

That's a type of red algae and your not going to like it one bit. Its the devil of all algaes and just as hard to get rid of. Here's a couple of articles on it to get you started on getting rid of it. Good luck!

Controling Red Algae

Rose

thanks for the info folks........we have algae eating shrimps in the tank but theyre too well fed on other stuff to tackle this stuff. i dont mind the look of its as long as it doesnt spread. maybe our barbs need a new bedroom