weird clear algae

Question
In the last week or less a kind of clear almost spider web or slimey looking something has begun growing on the lava rocks in my tank. It seems to be getting thicker and I have never seen an algae like this, if that's what it is. I tried to look at it more closely today and it looks almost moldy-ish. Do you know what this is and if I need to get rid of it and how? Thanks for your help.

Answer
Hi Shannon,

Yes, I have seen this "algae" before, but for me it has always grown on driftwood, not lava rocks. Sometimes the driftwood they sell at the pet store is not all the way cured, so part of it rots and forms this fungus...it's a pain. This is not algae but a fungus, feeding on decaying material. It is very bad smelling! To remove it completely, you will need to boil the rocks in a pot, or wash them with the hose and let them air dry for a day or two under plenty of sunshine. The good news is that this slimy fungus is not harmful to fish, in fact scavenging fish like plecostomus and most baby fish are known to pick at it!

The most common reason for this fungus appearing is uneaten food, so make sure you are not overfeeding. If a lot of the flakes or pellets or whatever you're feeding fall to the bottom of the tank, you're overfeeding. I usually feed my fish three *tiny* pinches, each one about half the size of the nail on my pinky. The small amount of food gets gobbled up quickly, none of it falls below the surface, and the tank stays cleaner. You might also try feeding Tetra's brand of crisps, these are very palatable and more stable in water so less goes to waste. Having a school of corydoras also helps cut down on uneaten food at the bottom, since they spend all day scouring the tank for food.

I hope that helps, take care!
Nicole