I thought it be cool to have a section where people can post Koi that they want to give away or want to trade for a different type of koi or fish. No sale of koi as a rule.

If someone wants to post such things, the pond and then fish section should be fine. This forum doesn't really have enough traffic for such trades, etc. to be that successful.

I would think it would be better to go thru your local pond or fish club. The fish wouldn't get as much stress traveling and most likely go to established ponders.