Anth, I also thought it would be a good idea. It was a disaster. When my big pond was built, I had a lot of the green oaks that had been pushed down moved into the bowl for structure. We got a big rain and the pond filled about 1/2 way. Within a week it turned blackish.
I wasn't worried. Like John, I had fished tea colored water in East Texas. I went ahead and stocked. Within 30 minutes, catfish, fatheads and bluegills were piping at the surface. Crawdads were crawling up onto the banks. Within hours they were all dead. I started calling around and very little was known about it. Then I talked to a couple of old time pond builders that had seen the condition. The oak tanins were lethal. I figured adding chlorine, like in a swimming pool, would clear it. I wound up adding enough chlorine to clear 2 Olympic sized swimming pools. The water changed color, a little bit. I tested with BG's in a minnow bucket but it was still lethal. I wound up having to pump the whole thing dry and letting the Texas summer eliminate the problem. BTW, the chlorine, according to Bill Cody, also leaches into the soil and creates its own problems when we eat the fish. With the help of summer heat and our frequent droughts the problem ended about 2 years later and I cautiously restocked. But, I first tested with some BG from my creek.
According to Lusk, the condition exists in certain types of soils but I don't recall the details. Nor do I need to. I just won't do it again. You can test it by taking some fresh branches and setting them in a wheel barrow full of non treated pond water. If it doesn't change color, you may be OK. However, as stated, I'll never take the risk again.
I won't even cook with fresh oak. I've seen the tannins discolor the meat on camping/hunting trips.
To me, oak is firewood. I now even test cedars which don't seem to have the problem.
