What is this white cobweb type stuff?

??? One of my tanks has this horrid white web like thing growing now and then, it appears all of a sudden and then seems to die down just as quick. I try to remove as much as possible but what is it? seems to spread on glass in a sort of mushroom pattern. I have green algae in other tank but have only ever seen one spot of white in that one on a plant and I trimmed plant to remove it.
Ideas?

 

This might be the bacteria building up. I have little white thready type bits, not alot, but you can notice them if you move something. if there's not much then its probaly this and this is nothing to worry about. if its alot, maybe try a water change?!

 

ty Gabby. I do many water changes every week as nitrites high since the pond snail population grew! Guppies are happy and slightly nuts. Could the white web be due to the snails?

 

I don't have any snails - so I wouldnt know if it was due to them - Sorry!!!

 

How much light does the tank with the white stuff get? If it's a fairly low amount it could be algae with low amounts of chloraphyl. How often do you clean that tank? It could also be mold/fungus from leftover food if enough of that sits long enough.

 

as it is a small tank I clean every week, most often twice a week. I think that I will have to move the tanks as I set them up in winter and now we have more light in spring I can see the two places aren't ideal! Shame,they are in the kitchen and we have a huge kitchen, big table and chairs and everyone hangs out there, will have to re-think!! just a little concerned about the stress of moving them plus i'd like to put Guppies in a larger tank and start again hopefully without snails as nitrites hard to control since snails.

 

as it is a small tank I clean every week, most often twice a week. I think that I will have to move the tanks as I set them up in winter and now we have more light in spring I can see the two places aren't ideal! Shame,they are in the kitchen and we have a huge kitchen, big table and chairs and everyone hangs out there, will have to re-think!! just a little concerned about the stress of moving them plus i'd like to put Guppies in a larger tank and start again hopefully without snails as nitrites hard to control since snails.

Yea, those pond snails and their eggs are hard to get rid of and in time may be a problem for your guppies. Some Loaches eat them, but then you need a home for the loaches. Another route is the snail-removing liquids at the pet shops once your fish are in another tank.