Pond Boss Forums GENERAL QUESTIONS Help Oily film on pond surface - 7/07 - Photos added!!

Hello to all! This is my first post and I sure hope I posted it in the right place.

Before I ask your collective advice, let me describe my pond: It's small, only about a quarter acre in size. It has an average depth of 6 feet. It has a raised bank all the way around it, so it does NOT collect any runoff. It only gets what falls straight down out of the sky. If the water level gets too high it goes out through an overflow pipe. The pond was dug in 1989. I have bass and bluegill in it - probably too many of each!

Okay - here's the problem: Every year I do battle with an oily film that develops on my pond. It's like somebody dumped a bottle of cooking oil or a very light viscosity motor oil on the surface. If the wind is blowing a little, it only covers about one third of the surface, as the wind pushes it to one side of the pond. When the wind blows really hard you'll find me at the end where the oil collects sucking it off the surface with a Shop Vac. The only time I'm able to put a dent into it is in late spring when the fuzzies from the local cottonwoods fall in the pond and sop up the oil...as the fuzzies collect on the side I rake them out and then I'm good for a few weeks before the cycle repeats.

This film does not seem detrimental to the fish and plants or any other wildlife...whatever this film is it did not originate on the Exxon Valdez! But it coats anything that floats in the pond (including me on my blow-up raft!!) with a sort of greasy film that's basically...sort of icky.

Where is it coming from and how do I make it stop?

Thanks in advance for any and all help!

Welcome to the forum, and you definitely found the right place!

I am betting it is the remnants of the break down of rotting plants on the bottom of your pond. As the plants rot and break down, a bi product is that "oily" film you speak of... Can you take a photo of this film? It may help someone ID for certain for you and help give you accurate advice.

Bill Cody the pond doctor may have another opinion on this, it seems to be right up his alley of expertise. Then again, what isn't up his alley of expertise when it comes to ponds?

Welcome to pondboss.

Do you have any filamentous algae(FA). FA will produce an oil.

I am betting a good aeration system for your pond would help control it... We'll see what others have to say though!

I do occasionally have filamentous algae in the pond. I recently had a pretty bad bloom that cleared up with a little Cutrine Plus.

I'll try to post some photos as soon as the weather cooperates. The film is not evident during or immediately after receiving rain and we'll probably be getting rain through Wednesday.

The fact that it disappears during rain and takes a little while to return even after the rain stops probably confirms CJBS2003's point that aeration would help...

weerdsteev,welcome to the forum,we're glad you found us The more info you can give the experts the better they will be able to help.Please send the rain to Texas when your done with it.We need it desperately.And oh yeah,the oily film on yer pond?Quit greasin yer fish.

Tom: Perhaps we get greasy rain over here? I've never greased my fish. Perhaps I should stop feeding them all those slabs of raw bacon...??

mmmmmmmmmmm..... bacon.....


install a bottom diffused aeration system and VERY carefully initiate routine (nightly) aeration.

dave - I don't understand that "VERY carefully" part. It sounded sort of ominous. How will I know if I've crossed over from very careful to not careful enough?

You dont want to startup an airiation system too quickly.Normal careful startup would be 30 minutes today,1 hour tommorrow,2hrs nextday,4 hours next day and so on until your up and running.Turning it on and leting it run full time from jump street could raise to much noxios gas to fast and kill your fish.Hey guys,am I paying attention or what.

And you didn't mention explosives even once.

Are you feeling OK?

It could be a new areation technique,but I dont think it would help the fish much.On the other hand,for green sunfish.....

Tom, one of us paid more attention than the other during aeration classes---not sure who though. I thought it was supposed to be 15 minutes the first day and an extra 15 every day after. THEN the dynamite. Or run the aerator for a solid 24 hours with a huge tarp over the top, then light the tarp-trapped Hydrogen Sulfide and Methane gas brought to the surface with an ordinary bic lighter for the pyrotechnics!

Teachers! OH TEACHERS! What is the startup sequence again? we're too lazy to re-read the dozens of posts that say.


Hey it's almost Juy 4th!

Hey! Strategically placed dynamite might just be my answer! Done properly, I could probably blow a large section of the surface water (the part with the oil slick!) clear out of the pond and over the bank!! I just have to erect a blast deflector in the middle of the pond and position the dynamite to the oily side of the deflector. If I'm lucky, my neighbor's cat will be on the bank when the blast occurs...

As I said earlier, I'll post photos as soon as conditions permit.

I think Weersteev and TomG might be related

rainman start with 15 mins and doubel it everyday. So takes a week to get you up to speed.

Yessir, here comes another oxygen crash. Fertilizer is gettin thick.

Hey,I think Im gonna like this guy,even if he's not in Texas.No offence WeerdSteev,but if you were closer we could play together.With dynamite.And beer.They go well together.

Okay...I'm ready to post a photo of my oil slick...how the heck do I do that?

(Tom - No need to be so formal, just call me Weerd)

feel free to flip to me greg@lakework.com and I will get it on our site gallery and link to this thread.

Wow, I've never heard anybody call Tom formal. I don't think anybody has even called him normal.

Greg - I just sent you the photos. If you post them to this thread I want everybody who sees them to know that the film has gotten quite a bit worse. Just to get some contrast in the photos, I introduced about 1 ounce of dishwashing liquid into a red-neck fountain I created just to break the stuff up a little. Had I not done that, the film was so uniform over the pond (no wind today to blow it to the side) you may not have been able to tell anything was there.

I consider formal=wearing socks...I do
Normal....whats that?

Note to self: never, and I mean never, invite Tom G to the Debutante Ball at the Waldorf-Astoria, ever.

(As if I would ever be allowed in.)

....unless, of course, it is a black sock event