parasites

Question
Hi, I have just built a small pond and whilst i am letting it cycle i have noticed loads of tiny worm like creatures swimming around (approx 4mm long)they look similar to tadpoles in shape and they swimm with asnake like motion. I have also been given a lily plant by my neighbour from his pond and am wondering whether they could have come from that as I had nothing else in my pond. any help re getting rid of these would be great, or would these be fair game foodwise when I put my koi in.Thanks in advance

Tony

Answer
Tony,

Sounds like tadpoles to me.  Frogs very often lay eggs in new ponds and they hatch quickly into tiny tadpoles, often thousands of them.  Here they are usually black, but they can be any color.  

They usually do no harm.  The fish usually won't eat them, but they mature quickly within a few weeks and leave the pond.

Good Luck,

John