That looks like hair algae and if it is, it is usually due to too much light.It is awefull to get rid of. TLC is what the water company uses and although I have tried it my success was limited when you consider the cost. You can get rid of majority by sliding your hand over the plant as it clings to your hand as you do it, but it does return in my experience.
Zev I was A postie in Rotorua (got bitten once too often ).
Caryl,fair comment but I promise honestly
Sarah I am glad you are my friend otherwise I would have been obliged to strangle Chris( I did not know you had stirring qualities).
Now I must leave and make a (humongous) effort to start this face saving article. :roll:
Do a water change pronto! There could be a few reasons. How big is your tank? How many fish? How big are your fish? Ph? Ammonia? Nitrate? Nitrite? How long has your tank been set up?
If you shop around you can get a very large tank for a lot less than $800. I bought A 2.4mx600mmx600mm. for $450. I bought another for $53 online and spent $300 fixing it.I also got A 3mx500mmx350mm for $450.
Driftwood will bring the ph down. I have a 900l tank with a large piece inside and my ph drops to less than 4 every week even though I do 50% water changes weekly.