Toxic pond?

[mariX]

The story started several months ago; I had that pond for several years with plants and koi and everything was going well outside the occasional raccoons visit. Anyway, 48 hours a week of heavy raining (you know the Southern California moonsoon like rain), my fish started dying; I am most of the time travelling around the country and I just had my spouse telling me everyday he had picked up some dead fish in the pond. By the time I came back none of them were still alive; I emptied my pond, cleaned it, refilled it, stocked it with new plants, waited a month and a half, checked the nitrite/nitrate levels, ammonia, pH, oxygen level.. all was a go ... and it worked for a month or so... until my daughter's turtle decided to leave her tank and jump in the pond. In a week, all fish were dead. Turtles usually do not kill fish especially since she was well fed but... I got rid of the turtle (found a new home), emptied my pond again (the turtle had killed all my plants), cleaned it, restocked with plants and waited again... last week after two months, all levels were ok at the exception of the water hardness which was atthe high end of the scale. I tried to stock my pond with new fish. this time they all died in 72 hours; no gross pathological signs on them : no ulcers, no hemorrhage, nothing. I have no idea what to do now, except giving up entirely and filling my pond with dirt. Do any of you have any idea of what could be happening?Thank you .

 

[dieselplower]

What kind of fish are you putting in there now?

 

[JohnHuff]

Welcome to the forum!
First of all, this doesn't do anything: "I emptied my pond, cleaned it, refilled it, stocked it with new plants, waited a month and a half, checked the nitrite/nitrate levels, ammonia, pH, oxygen level.. all was a go."

You need something in the pond to produce ammonia or add ammonia for the beneficial bacteria to appear. If you just fill it and stock it with plants, then of course the nitrite/nitrate ammonia levels will be "go", since plants don't produce the ammonia that you need.

Got to go watch Jeopardy, but will be back later...

 

[dieselplower]

Good point. What size is the pond and how many fish? What about the pump and filter?

 

[JohnHuff]

I tried to stock my pond with new fish. this time they all died in 72 hours; no gross pathological signs on them : no ulcers, no hemorrhage, nothing. I have no idea what to do now, except giving up entirely and filling my pond with dirt. Do any of you have any idea of what could be happening?Thank you .

Back from Jeopardy. After the fish died, did you check the water? If yes, what were the results?
Also, more info would be helpful as per Diesel's post.