Strange living thing in patio water garden

Question
Robyn,

I am new at water gardening and have two small gardens with plants, pump and fountain - no fish.  One of the fountains (approx, 12" square) has small black 1/4 inch long worm looking things (width is about the size of a # sign).  When the fountain is off they emerge and dart about and seem to be eating algae off the rocks.  The head is slightly larger than the body, and is triangular in shape.  I've searched all over the web to find out if this is friend or foe.  Any ideas?  I'm planning to bring the fountains in for the winter and not sure I want these things in the house.

thanks much,

Johnna
p.s. I have Anacharis in the fountain, but it doesn't seem to be controlling the algae like it has been in the larger fountain.


Answer
Do they have little "houses" into which they hide around the fountain?  Whether they do or not, they may be the larvae of one of the many species of midges or perhaps caddisflies.  My bug page is at http://www.fishpondinfo.com/bugs.htm
They are harmless outside but you might not want the adults flying around your house once they pupate. The good news is that most should be pupated before it's time to bring the fountain in for winter.  It's possible they are something else but I'd need more of a description or photos to say more.  A quarter inch is a bit big for midge larvae but some caddisfly larvae get that big.  They live in moving water.  Enjoy your ponds!

Robyn