We have a small pond (roughly 12,000 sqft) and I'm building a dock for it. It's going to be very basic 12'X6' with 3 pilings on each side

I just realized, is there something I need to treat the treated wood pilings with (or all the treated lumber) so that the chemicals in the wood do not harm my fish?

I searched the forum and surprisingly couldn't find anything about this but I'm sure there's something on here and I just missed it

Thanks for your input

I know old telephone poles aren't suitable due to the creosote. Some chemical treatments are definitely bad for the fish.

My fish did not get the memo about old telephone poles so they are doing just fine:)

Glad to hear your results, RAH. Me, I wouldn't take the chance.

The stuff used to treat "treated lumber" has changed a great deal over the years to make them less hazardous. Arsenic hasn't been used for over 15 years. Wikipedia gives a good rundown of past and current processes; it looks like mostly copper compounds are used today.

Lots of copper compounds used in pond treatment, but I don't know if the wood treatment coppers are a problem in ponds. Gotta be better than Arsenic, though.

I used them without any problems. Someday I might catch a one-eyed fish but intel then I think its. You don't really have a whole lot of wood that touched the water. Now there is a thought bout when it rains will the chemicals leech into the water. That I don't know yet but time will tell. What else would you use beside a metal or plastic material?

Part of my reluctance is what I see & smell at a creosote treatment plant about 20 miles from my home. They have a small pond on the property that smells & looks dead, even water birds won't go there. Probably accumulated chemicals, including arsenic, over the years. Don't want anything like that in my water, especially on the dock where I feed.

Agree A
They say not to line garden using RR ties. Treated bad also but a large pond it won’t hurt . Who knows what the long term damage is

I remember asking Bob Lusk about using treated wood from a junked porch in the pond. He did not recommend it. Perhaps it's like using oaks for habitat enhancement, it might be fine and it might not.

Ever hear the saying "The solution to pollution is dilution"?

Except when it comes to CO2, of course. There an increase from 0.028 percent to 0.041 percent of the atmosphere means the planet faces a dire emergency!

Actually my 4X4 pilings will be in the water

Did you see the part where I said the 4X4 pilings will be in the water?

I would hazard a guess that a typical pond in North America takes in more pollutants from the atmosphere in one year than would ever be
released from a few treated posts holding up a dock.

Is using treated wood in a fish pond ideal? Probably not.

Is it going to kill everything in the pond and give you cancer if you eat a fish? Probably not.

Yeah I seen that. I think you will be just fine. Heres what mine look like.

I think anything less then 15 20 yrs old should be fine, now I do know back in the day they used some pretty harsh chemicals to treat wood like creosote and supposedly there's arsenic in it but in today's world I think most of the really harmful chemicals have been outlawed. I wouldn't be too afraid of the new stuff, actually barely enough stuff in them to keep the post from rotting.

As the saying goes, "The solution to pollution is dilution." A way to find out is to look and see what amount is used to treat the wood then you might be able to find out what amount is leached out over time.

Personally? I would use them and not give it a 2nd thought.

Note that there are different treated lumber grades. There are grades suitable for ground contact, and water submersion, meaning they use a form of copper that does not dissipate into water like the cheaper Home Depot varieties do. 84 Lumber will supply the various types you need.

My dock pilings (4x4) of water submersion grade lumber is growing some bryozoans. If anything is a testament to being safe, it is those.

I would stay away from Creosote. Just because I hate the smell of that shiz when it gets hot in the sun.

A big Bryozoan