Please Help Identify This ... This ...

[Prime Ordeal]

If it's got little stems then it may well be a fungus, especially as it's taken hold on the wood. Is the patch on the filter exactly the same type?

 

[This Old Spouse]

It appears to be the same. They showed up at the same time, too.

 

[nurglespuss]

Does look to be cyanobacteria, at least some form. As stated do water changes and siphon it out as you do so. Have your water tested if possible for phosphates, high levels are the number one cause.

Wrong. Phosphates do not cause algae, nor do they cause cyanobacteria.

Wrong. They most certainly do. Phosphates may not be the problem here but they play a role in other algae.

Yes, freshwater. I keep this tank very clean, always have. 50% water changes each week. I just started dosing Seachem Flourish a few weeks ago. Could that be the problem?

No. Flourish is not the problem either.

I disagree.

There is a red type of cyanobacteria. Cyano is treated by:
1. manual removal.
2. blackout (between 3-7 day total blackout, depending on how bad it is)
3. increasing flow
4. increasing ferts (both of the last two to come into effect as soon as the blackout ends)

You're taking a very simplistic approach to the subject. There are numerous interacting processes that lead to algae (or cyanobectaeria). It's that very reason that makes it so difficult to totally eliminate all algae in the tank at all times.

Perhaps it's time to get that Siamese Algae Eater you've always secretly wanted but could never justify.

Actually you could try moving the bristlenose plec in to see if he likes it.

If it's cyano that won't work - nothing eats cyano. However, if it's algae then it's possible that an algae eater may take care of it. You'd have to ID it definitively first though.

I'm not convinced it is cyanobacteria although I admit I'm not sure exactly what it is. It looks more like an algae to me.

+1