# What are these donut-shaped things on my glass?



## NUGGET79 (Dec 3, 2020)

Found these tiny, circular-shaped formations on the glass of my quarantine tank this morning. they’re really tiny so it was hard to get an in-focus picture.

There’s also a little bit of white stringy looking stuff to the right of them. I first noticed the stringy stuff yesterday. I was wondering if that could be new roots from the fern growing up the glass because it’s gone nuts in there and there are roots exploding all over that corner of the tank. T


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## Louis (Apr 23, 2014)

The doughnuts are small colonies of some kind of funghi or bacteria growing outwards from a central point and probably harmless. I keep the front glass of humid vivariums spotlessly clean but tend to leave the side panels alone as I find that all sorts of small isopods, springs, worms, mites etc. migrate up there at night to feed in the biofilms like this that form on them.
The stringy looking stuff may well be a variety of slime mould which again I have never found to cause any obvious harm in a vivarium and which tends to disappear as quickly as it appears. 
These biofilms can be quite interesting to observe in and of themselves, seeds of Primulinia tamiana and some sort of weed I have growing, that actually explosively fires it's seeds across the tank when the seedhead is distrubed, regularly germinate in the biofilm that forms on the side panels in some of my tanks.


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