I just released the Common that jumped out back into the pond today and the other 2 Commons are chasing him relentlessly. Is this a bad sign? Do I need to separate them? The water in the pond is very muddy looking and this only happens when there is A LOT of activity happening under the water so that tells me they've been swimming wildly around for a couple of hours.

Sorry, couldn't wait for a reply they were killing him.

If the fish are swimming wildly you may want to check the ponds water params. Swimming wildly and jumping out can be signs of toxic water.

Or maybe the fish are spawning and that's a female they're bullying and chasing.... If she's getting beat up you should separate her. Do you have a way to separate her?

I also think you should check your water for ammonia, pH, nitrates, nitrites to make sure everything's alright.

I was just thinking what gardengirl was thinking, breeding behaviour?