freshwater sponge or soft coral, what did I see???

[quippy]

I thought as soon as you described it that it sounded like a colony or two of bryozoans (Ectoprocta). I'd never heard of freshwater soft corals, but bryozoans can form coral like shapes. If people regularly dive at Stoney Cove, surely there's a picture somewhere?

The mystery continues.

[Madcaravanner]

Just checked my photographs and unfortunately all I have of Stoney is surface video of my final cert dives
Did think I had some stills somewhere from the instructor Mike but these seem to have got lost

[DivingBatgirl]

Sorry I took so long to get some photos of these creatures. The photos were taken by the dive manager at Stoney Cove and he informs me that they have been growing there for several years.

There seems to be two different species.

Can anyone identify them please. I would love this mystery to be sloved.
Thanks

[The Woodman]

Hi DBg

I think your "coral" is a freshwater sponge, possibly Spongilla lacustris , although this ID should be treated with a certain amount of caution as it is from an image.

What does concern me is that the images show a non-native alien species - the Zebra Mussel Dreissena polymopha.