A mass of 5mm black/brown "caterpillars" - ID please

[Expatscot]

Hi,

I went out last night to sort out my pump/fountain, which had a much reduced flow rate.

What I found was not the ususal pondweed covering the inlets, but a mass of small (5mm) dark brown or black creatures. They seemed a bit like little caterpillars in that they moved by wriggling their bodies and picking up their "heads" to find a new anchoring spot.

My fountain pumps through a hole in a rock and then falls down about 30cm over another rock. The lower rock had a thick mass of these beasts - maybe 1cm thick most of the way down. They were also in the actual tube through the rock - when I poked a stick in, large black clumps of them fell out. There must be hundreds if not thousands of them.

My fish haven't been eating their food as ravenously as normal recently, which I had ascribed to goldfish eggs and babies, but maybe this is what they've been eating!

Anyone got any thoughts?

[Paul mabbott]

Could they be anything like this? Mosquito Information: Larvae - WUVCD

mosquito larvae?

[Expatscot]

Hmm, they don't look like those, I'm afraid.

I've been out for another look and have managed to find some - I'll post pictures as soon as they are moderated.

Looking more closely, they seem to have a greenish tinge at points, possibly the segment joints. Movement is by planting the tail, extending the head, planting it, then whipping the tail round so that they are bent double as the tail is re-planted.

[Paul mabbott]

Originally Posted by Expatscot

Hmm, they don't look like those, I'm afraid.

I've been out for another look and have managed to find some - I'll post pictures as soon as they are moderated.

Whatabout bloodworms? How to raise your own blood worms, Chironomidae, with pictures ?

Incidentally, if you upload pictures to the 'unidentified' or 'forum' galleries, they don't get moderated so can appear on the forum very quickly. Indeed, until they're identified, they should go in the 'unidentified' Gallery!

[Expatscot]

Oops...

OK, here are the photos (I hope):







They don't look like the bloodworm to me as the head seems different, but I'll bow to any better informed opinion!

[Paul mabbott]

I'm hardly 'better informed' on these things - I'm sure someone else will tell you in an instant. My best guess would be tipulid (cranefly) larvae .....

[AndyC]

This is a possible not a probable

They might be blackfly larvae, they are found in running water and I think they move in the way you describe (but I might be wrong!)

If you google for pictures of simuliidae larvae you will find some that look similar to yours, this is about the closest I could see Google Image Result for http://www.troutnut.com/im_underwater/picture_86_medium.jpg. Click the picture at the top of page to enlarge.

Andy

[Expatscot]

I agree they certainly look like the blackfly image - I think the smooth head section distinguishes them from most of the other larvae I've seen in my hunting.

One thing's for sure, if they are all blackfly, I hope the fish get a good feed!

Allan

[Venger]

Originally Posted by Expatscot

One thing's for sure, if they are all blackfly, I hope the fish get a good feed!

Allan

Before they get a good feed on you! - they do have a nasty bite when adult.