Brown Algae?

[RossyBoy]

Guys i've noticed my plants collecting up a layer of brown matter and also on my filters?

Does this need treating?

One fish is very ill aswell, just sat on the bottom aimlessly? Should i act and seperate or not????

 

[QTOFFER]

The brown stuff is probably just diatoms - a normal stage of tank maturation. It's ugly, but completely harmless. You can easily remove it from surfaces by gently wiping or holding the object under running water, but it will likely reappear. Eventually it will stop coming back on its own.

Is the tank newly set up? Was the sick fish recently added? Do you have a test kit? You should test your water for ammonia, nitrites, nitrates, and pH and post the exact results here. Most lfs will test water for free.