KurtG wrote:
wrote:
They could be, if they move.

Definitely not then. These are calcified to the rocks.


Hi Kurt,

It's impossible to say for certain without a good photo but your
description sounds like Spirorbis spp.

Spirorbis is a sedentary polychaete that builds a tightly coiled
calcium carbonate tube. They are known to occasionally 'bloom' in
aquaria, presumably in response to food availability. I believe they
generally disappear just as quickly (and mysteriously) as they appear.
They are filter feeders and present no threat to your tank. OTOH: It's
possible that their appearance could be a secondary symptom of
excessive nutrients in your water (the primary being the appearance of
whatever phytoplankton or bacteria they eat).

You can see quite a lot of detail at about 20X magnification but an
ordinary magnifying glass ought to enable you to identify them to
genus. Here's a picture for comparison:
http://www.biopix.dk/Photo.asp?Langu...&PhotoId=18604


Vermicularly yours,

Alex