Hi over the past week or so my pond fish have been acting weird.
I have Koi, Shubunkins and Goldfish in a large pond and recently they have not been themselves.
They are all acting lathargic not coming up for food when normally they would go crazy for it and some are displaying worse symptoms.
Some have blood streaked fins and redness on the body. I can guaruntee there has been no chasing or bullying and the fins don't seem to be erroding so I can't point out the exact cause of the illness.
It is not overly cold but for an English summer it has been crap but not cold enough to cause hibernation behavior.
I need help with a diagnoss cos there is alot of money swimming about in that pond and I don't want to lose it.

It sounds like they have septicemia which causes the red veins on the fins to become obvious. Septicemia can result from poor water quality, stress, or almost any illness. Have you tested your water? If so, what is the temperature, pH, hardness, alkalinity, ammonia, nitrite, and nitrate readings? How long has the pond been set up? How long have their been problems? Has it rained a lot?

Not knowing for sure what is wrong, I suggest testing your water. I also suggest a 10-20% water change with added dechlorinator even if you have well water because it also helps deactivate heavy metals. Also, add 0.05% pond salt if you don't already. That helps with many things. Finally, they fish might need an antibiotic if they have a bacterial problem. Hopefully, they are just feeling off because the water chemistry is off, and that can be fixed normally.

Good luck!

The pond has been set up for years with no major problems other than the occasional outbreak of fungus but that was sorted out.
A water change was preformed drained by about a quater and topped up with a little salt.
My talley shows that 15 goldfish are sick with the koi toughing it out by swimming a bit more and eating a little.

Are anitbiotics only avaliable from a vet ? or can you get some from a pet store.
Also how urgent is the treatment required ?
If they were my fish they would be being treated already, but they are my dads and he ... well just sees them as fish and he can buy more if they die which is not the way to see them.

If the treatment is only avaliable from a vet I will try and get some and try to save as many of them as possible, I feel some are too far gone and may die regardless.

Get going on testing the water and doing any fixes that are needed...don't forget the salt. drsmithfoster.com has some anti-bacteria/fungal food on sale right now, but Robyn and others better help you with that, I have NO experience except treating with salt. I have to admit I was NEVER a fish person ( sounds like your dad ) but the pond has changed my ways. The pond has taught me and hubby that fish have different personalities ( ours act more like dogs than cats ). lol I needed to touch and interact, have your dad hand feed, I bet he'll get hooked. lol :D

Aquarium and pond stores sell many kinds of antibiotics, too many to list. The most important thing is water quality. If it's good, many problems clear up on their own. I hope you can find some antibiotics. Be aware that some kinds like penicillin will kill the good bacteria in the biological filter which will result in a spike in ammonia and/or nitrite which can be deadly. I used it once in an aquarium years ago; it wiped out all but a few fish and my pleco who is still alive a decade later. Two antibiotics I know are safe are erythromycin and minocycline which I've used often.

Thanks for that info, after doing the water change their conditions don't seem to have deteriorated.
Now a new odd behavior has started, jumping and splashing by the big koi.
They have never done this before could this be down to the bad water as well ?
I am not overly worried about killing of the bacteria as I have bacteria food that helps it come back if its lost throgh overdose of medicin or a fresh start tank/pond.
We are in the process of giving the 100% fresh water with all ther necesery de-chlorinating and anti metals it need to make it safe. this is being done gradually and carefully to avoid furthur stress.

When fish jump out like that for reasons other than spawning behavior, it's usually due to something being off in the water. They literally want to get out of the pond and hope to flop somewhere else.

What do you mean by bacteria food? The fish waste is the bacteria's food.

How are you doing the 100% water change? I assume you took the fish out?

I hope things improve.

Had the water tested and all things are great, the oxygen was a little low but not dangerous.
Apparently in the UK courtesy or our odd weather of late there has been a swathe of pond fish being ill. We got a diagnosis of a parasite infection being the root of the trouble and this may have caused the septicimia.
At the store where we got the medicine they have had the same complaint put to them for months and we were not the last. !
As of now the full change is on hold while they are being treated and so far so good, they have even begun eating again not quite as greedy as before but it's a good sign.[B]

What kind of parasite did they say the fish have? Did they actually see the parasites, or are they just guessing? Weather won't create parasites where there are none.

What was the actual oxygen reading in ppm if you know?

I don't know the actual oxygen reading, the test was ment to go bright pink and ours was fairly bright pink so nearly normal levles.
As for the diagnosis it was a accurate summation based on recent events the medicine we got treated everything from white spot to gill disease, and they must have had one of the things it treats cos they are getting better day by day !.