"'Mike'" wrote ...

No fish in there before. The pond dried up a while back and the few fish in
there died, dispite efforts to save them :-((
No the pond was clear.

But how long ago? If a stream flows into the pond then fish fry can come in
too and they would grow well with little competition. They can even come in
as eggs stuck to the legs of wading birds. So, if it's a few years ago that
it dried up there may well be a few native fish in the pond again now.

Don't think we have anything like the annual Killifish in this country
unfortunately.
http://en.wikipedia.org/wiki/Killifish

--
Regards
Bob Hobden
W.of London. UK