Fish Deaths.

[bok]

Hi Mr wiggly

 

I've been keeping koi, mirror, leather and common carp for over 20 years now.

 

The most likely cause when fish die with no signs of any disease or damage etc at this time of year is bacterial, It leaves no sign and can kill only a few fish or the whole pond.

 

When temperatures go down as low as they are now fish emmune system shuts down hence they have no defence against bacteria, bacteria can get into your pond easily from birds and or bird droppings amongst other uncontrolable sources.

 

Its easy to get hold of treatment for bacterial infections to put directly into you pond water pond fish shops / dealers etc. and will not harm your fish plants etc.

 

May be worth trying that as it won't cost you much and from my experience its nearly always the culprit when no signs are present on the fish.

 

Hope this helps.

[egbert]

i don't know much about fish keeping but it sounds like you had some huge fish in that pond but i didn't think that you would ever be able to keep 14 pound carp in a pond maybe they got to big and just died because there wasn't much room

[lazy hooker]

hi

 

i've kept koi for a number of years now and after sudden deaths you need to check the water which although looks clear with no algae or blanket weed you need to rule out poisoning from nitrates and nitrites, ph can change and ph also needs to be checked.

 

if this is ok then i would be looking at something which no one has mentioned yet - Parasite infection....you need to get a microscope and "scrape" some mucus from the gill areas....parasite WILL kill and if they don't can lead to secondary bacterial infections ...you can treat with an antibacterial but unless you identify what type of parasite then your just going to get re-infection after re-infection.

It is alao good housekeeping to treat the pond in spring and autumn with an antiparasite as you get population spikes during these times.

 

lastly and it has been mentioned and going by the time of the original post (sept) you may have had a storm or the weather atmosphere can change stopping the exchange of oxygen in the water, you can't really beat an airator even if you have a waterfall.

 

cheers

 

john

[MrWiggly]

Thanks to all for suggestions and advice ..

 

Been a few months now since the "outbreak" .. and I still can find no reason for it !! Water quality/Parasite check showed nothing amiss.

 

What puzzled me was it was just the big ones that were going under !! Over winter the medium and small/fry fish appear to be fine.

 

Still Bl**dy odd !!!

 

Wiggly.