I understand your frustration but we cant act till we have all the facts including all your water perameters .
From now onwards uless viewing your koi I would run a couple of airstones in your pond 24/7 365 days a year
One of the first basic mistakes a novice does is to not QT their fish, weve all been there mate it causes no end of trouble and worry .
Maintenance of your filters and routine partial water changes are needed.
The bottom of your pond should be kept clear of detritus dead and decaying leaves etc especially in Autumn .
Another thing your novice does is overstock I've counted 15 in your pond already and your only 950 gallons more than us we have around about 10 koi .
All serious koi keepers own a microscope in time I can teach you to do your own scrapes of mucus from your koi to tell which parasite you are up against .
Our own Microscope is a BresserNG x40-x1024 with occular we do a routine health scrape at the start of every season and to tell if a new koi is free fromparasites that may attack your own koi or even vica versa .
Routine Quarentine lasts up to 8 weeks , a good suggestion we founded the Plymouth and District Koi Keepers Society way back in 91 we are a section of the Parent organisation The Brirish Koi Keepers Society [BKKS].
The BKKS has a list of Societies on their website but thats down under reconstruction
You can always join the nearest section to you and have people who like ourselves have fish health knowledge that will be more than willing to come over to give you a visit and mentor you through the first year of keeping.
The list of books I gave you the link to has the titles that all important ISBN number [where possible] and the authors name/names.
A good first book for you would be :-
The Interpet Manual of Koi Health ISBN 1842860992. Keith Holmes, Tony Pitham.
another :-
Hand Book of Fish Diseases (All Fish) ISBN 0866227032. Dieter Untergasser.
One thing you need t learn straight away is net work with koi as damage to the mucus membrane through bad netting is a sure fire route for parasites :-
https://www.gardenpondforum.com/articles/how-to-correctly-net-fish.17/
Dave
From now onwards uless viewing your koi I would run a couple of airstones in your pond 24/7 365 days a year
One of the first basic mistakes a novice does is to not QT their fish, weve all been there mate it causes no end of trouble and worry .
Maintenance of your filters and routine partial water changes are needed.
The bottom of your pond should be kept clear of detritus dead and decaying leaves etc especially in Autumn .
Another thing your novice does is overstock I've counted 15 in your pond already and your only 950 gallons more than us we have around about 10 koi .
All serious koi keepers own a microscope in time I can teach you to do your own scrapes of mucus from your koi to tell which parasite you are up against .
Our own Microscope is a BresserNG x40-x1024 with occular we do a routine health scrape at the start of every season and to tell if a new koi is free fromparasites that may attack your own koi or even vica versa .
Routine Quarentine lasts up to 8 weeks , a good suggestion we founded the Plymouth and District Koi Keepers Society way back in 91 we are a section of the Parent organisation The Brirish Koi Keepers Society [BKKS].
The BKKS has a list of Societies on their website but thats down under reconstruction
You can always join the nearest section to you and have people who like ourselves have fish health knowledge that will be more than willing to come over to give you a visit and mentor you through the first year of keeping.
The list of books I gave you the link to has the titles that all important ISBN number [where possible] and the authors name/names.
A good first book for you would be :-
The Interpet Manual of Koi Health ISBN 1842860992. Keith Holmes, Tony Pitham.
another :-
Hand Book of Fish Diseases (All Fish) ISBN 0866227032. Dieter Untergasser.
One thing you need t learn straight away is net work with koi as damage to the mucus membrane through bad netting is a sure fire route for parasites :-
https://www.gardenpondforum.com/articles/how-to-correctly-net-fish.17/
Dave