Sorry for your loss Grandmapoo.
I've noticed an oily film over my ponds too, when DH cuts the grass. I'm not sure how to avoid that. Maybe if you think someone is going to be using a gas powered tool alot near your ponds you could cover it with a tarp?? I was amazed when I first found oil on the water. Doesn't seem to take much. Plus....think of what those working with the tools must be breathing in!

I just asked the DH what makes those oily looking spots on the water, duhhh (usual answer) he had just mowed. I worry about them, but no fishy deaths.
Debbie

Awwww Poo! I'm sorry your fishies died! :*-( Thanks for the warning.

How did you remove the oily film from the surface of your pond?

C3D

Do you have a submersible pump? That may be the culprit.....

Speaking of submersible pumps.....just recently I noticed a film on my pond surface. When I removed my submerged pump and filter, I could smell the odor of the oil leakage. It was a Beckett pond pump and I bought it just last fall. I had to do a water change and could tell the fish really appreciated it. Luckily, no damage was done to my fish or pond plants. Whew!
Just thought I would comment on mstrseed suggestion.

Happy Ponding,
Jackie

Thanks Chicka and Catherinet. I tried to skim the surface of the water and remove a little water. It helped, but there is still something there I can't see. The fish food still spread, but not as quickly.

My little pond has no filter. It depends on it's own little ecosystem. I can't do too big of a water change at a time, b/c it will through it out of balance.

CD3 you can let your pond overflow and the oil should run out in the overflow. Don't know if this would the correct answer for everyone, but it worked for me with some trash that got in my pond once. Glenda

They say a heron will put film on water and also sopmething dead.Or like another poster said your equipment may be leaking oil

It is also entirely possible the oily film had nothing to do with the fish deaths. You mentioned you have no filter?? Little fish fry are very fragile, delicate creatures. They are easily damaged by poor water quality. Do you have a test kit? Test your water for pH. Also check for ammonia and nitrite. Do you have rocks or any build-up in the bottom of the pond? If so, you may have a deadly gas called hydrogen sulphide in that muck. It is impossible to maintain a pond with fish as a "perfect eco-system" since you have fish causing pollution in there and no system in place to deal with the ammonia that is produced. In nature, a pond has no filter, but it has a constant exchange of water going on. You don't have that. You have the equivilant of a stagnant swamp. I don't mean that as an insult.....just a comparison.

I do clean my pond and do water changes, no rocks or debri. I've had the pond for years with no fish deaths, only from the dogs going swimming. There had been a ph change from all the rain, but it wasn't significant. I'm sure it's the oily film that caused the deaths. My main concern with my pond is the oxygen level which drops in early spring when the plants aren't established and feeding starts.

Glenda, that's a great idea! Thanks. :)

If you have an oil slick there are absorbant pads available that only collect petroleum from the surface of the water. They float and might be the answer for your 'slick'. Should be available at a safety supply store or you might try your local fire hall. I'll bet they would be willing to donate a pad or two for your small pond. Good luck

I overflowed the pond yesterday evening as Glenda suggested and it worked. I built my pond with a gentle slope making a lower side with a little concrete spillway that my bench sits on and the overflow process worked perfectly.
Afterward, I sprinkled a few flakes and they didn't skid across the water, just floated there as they should and the fish came up to eat! I'm so relieved!

Thanks for everyone's comments and concerns. :)

That's great news, Poo! :-) Thanks for the idea, Glenda!

Your other fishies OK then?

C3D

We took a 30 foot tree out that was 5 feet from our pond with a chainsaw....other than netting wood chips that flew from the pond there was no problem with the fish or plants.This was a year and a half ago. Are you sure it was the chainsaw exhaust?

My cat almost killed my two goldfish.

How? It lays on the screens I put over the water.

One day I found a half wet cat and a screen skew. The next day, the fish were gasping for air, there was a film over the water, all the algae had died and the water changed from green to brown with big bubbles forming.

I think falling in the pond scared the crap out of my cat. Literally. So when they talk about dissolved organic compounds, these can be a problem in a flash (and not necessarily from poor maintenance).

I did a 50% water change, cleaned the filter, kept cleaning the filter daily for several days (am still cleaning the filter).

Chicka, all the other goldfish are at least 3-4 yrs old (much larger) and they show no ill effects, thank God. Only problem with them was they would not come to the surface, probably instinct. I really thought I was going to have to get rid of my pond. It's not the greatest, but I do love sitting by it and watching all the wildlife and nature.

Another thing I noticed was a snake skin, but garter snakes get in the pond every summer and have never left an oily film and they don't leave dying fish behind. I try not to get upset too much when the snakes eat some fish. They keep the number of new fry in check.

I welcome all nature to my pond, except man made pollutants! ~~~~grrrrrrr~~~~ ;)

I find it extremely hard to believe a running chainsaw will produce so much pollution that it would result in a scum on your pond. Most of the exhaust is blown away from the site by the wind.

One thing that may be a good idea is a little activated carbon. That stuff is great for getting out lawn treatments, tanin, or any other foreign chemical. Most pond or fish places usually have it. Just read dosage and put some in a fine mesh bag wherever gets the most water flow. You may have got the 'slick' off the top, but there could easily still be nasty chemicals in there.

The oil slick came from the bar oil the saw uses to lubricate the chain going around the bar. The excess flies off the chain when operating. The damage could have been prevented by aiming the saw away from the pond when cutting. Some bar oil is now made from vegetable oil to be more eco-friendly than petroleum based oil. It will still leave a slick on the water though.

botann - that would make more sense, but the OP did not say that. The tree was several yards (at least 6 feet away). another poster has the same problem with a lawn mower???

Papertowels will absorb oil at the surface.

Buy only mag pumps that don't use oil.

Ask your neighbors to chainsaw elsewhere!

I mow on one side of my pond and aim the exhaust the other way. Or, one could hand trim the grass around the pond, or better yet, plant flowers, shrubs, and groundcovers so you don't have to mow or weed whack near the pond edge.

Is it possible the spilled gas/oil when filling the chainsaw? Simple exhaust doesn't sound like it would cause this. But I have been wrong before!! haha