What do you suppose ate my koi?

[Frankie Stapleton]

Updating this inquiry about missing or dead koi...my friend in HPP had about 100 small gold fish in her outdoor pond with several larger koi and all but about 10 or 12 of the gold fish disappeared apparently overnight. That's quite a bit of small fish! At least several dozen!

She is wondering what possibly could have done that. One of the larger koi has a smaller than dime-size white spot on his nose that is perfectly round like a tumor but is a bit ragged 3-dimensionally. I mentioned that the night sky has been particularly bright over the past week (due to the full moon and unusually cloudless skies) and suggested birds, hawks, owls. She has dogs loose in her yard at night and mongoose are daylight predators.

Also, the remaining fish seem lethargic and several kept hanging out by a bit of a crevice in the pond's rock wall. What do you all think is going on here? No one has used any chemical spray nearby. Surely the vog down Kaloli Blvd. hasn't been strong enough to acidify her pond, do you think? And does anyone know what ph of water is ideal for pond fish?

Thanks for any advice...[8D]

[dmbwest]

Any footprints in the sand so to speak ?

Trampled surrounding plants or displaced rocks in / around pond ? ?

Maybe a person wielding a net.

aloha,
pog

[Carey]

Koi are best in fairly neutral - slightly basic (7.0-8.0 pH) water, but quick swings even in that range can wack them for a loop...

I would doubt that the water got them...as the fish disappeared - bad water usually makes floaters & sinkers.

If the spot is indented, most likely a bite or scrape, if it is raised, might be a bump or infection/reaction.

BTW: A good sized heron can down a nice quantity of small fish...esp if it hasn't eaten in a few days...look for their nice sized footprints along the edge -they can hunt with one foot tucked up...so may only find one footprint

[Frankie Stapleton]

Thanks for all the input. There were no footprints around anywhere, no partially eaten bodies or any other clues. My friend was on her way to pick up ph test strips when she ran into a gentleman who is a pond man and has lots of experience locally with fish. He told her to flush out her pond with running water as sometimes a frog or toad that has been elsewhere in the yard and picked up pesticides on its skin will get in a pond and the concentration of pesticide is enough to kill other life in the pond.

She flushed the pond and now the remaining fish are looking very lively, not lying around like they were, eating again and li' dat. So she is gonna get after her hubby who has some company come in and spray elsewhere in the yard for ants every coupla weeks or so.

These incidents, like the dying off of bees, are signals to us humans, like the proverbial canary in a coal mine. Thanks again to all who shared their insights....aloha, frankie

[grumpyscosmos]

Watch out for a family with a Southern Accent...lol

[jsims]

Well, you could not rule out that a couple of really hungry cats pulled this thing off but considering that they are not really that used to water, I would suppose that they are not the real culprit here.

Then your next bet that some birds with really strong beaks are the ones who did that. It is sad that they have to go through that, though.

[DTisme]

An electrician recently told me a story about a pond where all the fish died overnight - seems the house wasn't fully grounded (half was, half wasn't) and there was an electric pump and you know the rest.

[missydog1]

Frankie, sounds like maybe more than one factor was to blame. As you had no floaters, something or someone ate or carried away the small fish. Koi do eat smaller fish. I learned that the hard way when my koi ate all my swordtails.

When we don't have a lot of rain adding fresh water to a pond, the water can get poor. Too much ammonia is one problem I've had. Or PH wrong, but honestly I haven't had problems with PH ... my pond is all rainwater and no issues. But when no new water is going in due to no rain, fish do get sluggish.

When the ammonia gets too high they will be poisoned and start swimming sideways or upside down, losing control of swimming, then die. In an emergency, they can be netted and put in some clean treated water while the pond gets a water change.

When the water gets bad, they will seek out the spot in the pond where they get the most oxygenation and will hang out there.

Glad to hear things are better!

Re cats -- I used to worry about my cats as they are both hunters and there are ferals around too. In seven years I have not lost a fish to a cat. However, herons are notorious for "fishing" koi.

[Frankie Stapleton]

Thanks, Kathy. I'll pass this on to my fren. Thanks to all of you who cared enough to reply. However, I am a Southerner...