Everything dead in pond...DEET, Round Up and or what?

[scrapperluv]

Hi all,

I have a 70 gallon pond and I've been loving watching the tadpoles and guppies hatch and grow in it since May. We have TONS of tree frogs from the tadpoles I put in the pond last year and all was well all summer. I have a couple bowls in the house with tadpoles in them, too, so my kids can watch them develop.

I went to scoop some fish and guppies out of the pond two days ago and all of them were dead. I had a HUGE population and was going to remove about half of them and donate them to my daughter's school...but no, nothing left. So I checked the bowls inside of the house and half the tadpoles were dead and the rest dying. Then realized, the night before I had taken plants from the pond and added them to my bowls in the house. The plants must have transferred something toxic.

Here is what could possibly have gotten into the pond. It would have been such a low concentration, though. Last week 2 different weed killers were sprayed in my flowerbeds that are about 50 feet from the pond. Last month bifferin insecticide was sprayed a couple feet from the pond. I work on the pond with DEET on my arms, but I'm pretty careful not to spray near my hands or forearms. I suppose any of these could have done it, but how weird that it transferred to my bowls via the plants. Any ideas?

Now what do I do to make the water safe again? I drained most of the water and refilled it today & added dechlorinator. Then added 6 feeder fish to see if they'd die. I bet those fish are tougher than tadpoles, though. Do I need to completely drain the pond and clean it so tadpoles will thrive in it? Oh, and there are brand new eggs in the pond this afternoon. FYI, the snails survived and the plants are very healthy looking. We have water lettuce and hyacinth in there.

Thanks for reading my long post!

 

[Meyer Jordan]

It may have been insecticide related or it could have been something else entirely. Small outside life-supporting water features often maintain a fragile balance both chemically and biologically. It could have been just too many tadpoles.

 

[scrapperluv]

Good to know. Next time I have a huge batch of eggs like that I'll remove them before they hatch. I have a feeling overpopulation might have caused some type of bacteria to grow. Weird that it transferred to the bowls inside on the plants, but I guess they could have been carrying it.

 

[Mmathis]

Hello, and sorry to hear about losing the critters. From my experience with tadpoles is that they are very sensitive to their environment, so anything from inadequate filtration to overcrowding can be an issue, as @Meyer Jordan said.

 

[MitchM]

In case it was from fatal exposure from an insecticide, you could try running a small pressurised filter containing activated carbon.
That will help remove many different contaminants.

 

[mgmine]

With only 70 gallons of water I would dump it completely, hose it down and start over.