QUOTE(Ashraf Farid @ Jan 16 2015, 09:49 AM)
Tzuen, I really think it looks more like diatoms than fungus....
Fungus tends to appear on wood, or something organic that they can feed off of.
Thanks Ashraf. Just google, and i hope this option works.

Brown Algae (Diatoms)
Diatom Algae
Brown Algae, or diatoms, often present themselves as a brown, muddy, muck that covers plant leaves and hardscape items. It is rare to be seen in a fully established aquarium.
Causes:
Newly setup tank – Aquariums that have just been setup seem to be prone to diatom algae.
Excess nutrients – Silica in particular appears to be a trigger. Contact your water utility company for a report detailing silica concentrations in your water supply.
Possibly old bulbs – Sometimes, old bulbs can encourage the conditions for diatom algae.
Cure:
Time – Allow it to use up the excess silica, and it will often disappear on its own.
Manual removal – Siphon/scrape diatoms manually for quick removal.
Algae Crew – Otocinclus and Nerite snails are fantastic at clearing a tank of diatoms. They help with other sorts of algae as well.
sos