Hi,
I am new to using group chat rooms so please forgive me if I get things
wrong.
I have a kidney shaped garden pond which is about 6 feet long and 4
feet wide and about 3 foot deep at its deepest point.
I have a mixed bag of about 12 fish, some gold fish some small koi some
Sensung Carp and also quite a number of tinny little stickle backs.
Everything has been fine for years until about five weeks ago I found a
dead goldfish on the top.
On examination I could see nothing wrong with the dead fish and just
put it down to old age or some natural cause and left it at that, and
then a week later I found another and again just thought it might be
the hot weather or something.
After I removed the dead fish I treated the pond with Medifin, just in
case there was something happening that I could not see.
All seemed ok until this week and yesterday I found one of my Sensung
carp dead.
I have tested the water for the usual things (PH
Nitrate/Nitrite/Ammonia) etc and all tests came out fine.
I have a few other possible theories that may be the cause but would
like to hear from anyone who can confirm or dismiss any of the
possibilities.
Firstly growing above the pond, I have a large purple lilac tree, which
because of the humid and hot weather has shrivelled up the flowers and
turned them into the brown seed heads that I get every year but not
usually this early which have dropped into the pond and I think may
have contaminated the water, as the colouring of the water was quite
brown..
My question is this: - Is lilac toxic to fish?
Second strange thing which is happening is I kept finding whole & half
eaten peanuts on top of the lillie leaves and the other day found out
that it was blue tits getting them from my neighbour's feeder and
dropping them into my pond.
My question is: - are peanuts toxic to fish?
Finally My lillie which normally gives me half a dozen leaves and a
couple of flowers a season, has gone mad & produced so many leaves that
it covered the whole pond which I didn't do anything about because it
kept any algae from growing.
My question is two fold: - Why has it suddenly grown massive (Is it
because there is something in the pond that it likes? but is also
killing the fish). And could anyone tell me if the lack of sunlight to
the fish might be giving them a vitamin D deficiency or something?
Sorry if I have gone on a bit, but I wanted to let you have all the
facts.
I have now changed 75% of the water which was brown and is now looking
really clear & clean &I have re-dosed with Medifin.

Any help provided will be very much appreciated.

Regards
Martin Lowe