Whether you are buying, selling, trading, or giving away, it helps readers to let them know when the item is no longer available, or the wanted item has been found. So please consider editing the subject of your original post to reflect it, to save readers from inquiring further about items that are no longer available. The easy way is to click the "Edit" button in the upper left of your original post, and then append "SOLD" or other designation to the original subject line, as shown in bold below:
Examples:
For Sale: AquaClear Filter - SOLD!
Wanted: Black Ghost Knife Fish - FOUND!
Looking to Trade 20L Aquarium - TRADED!
Free Guppies to Good Home - ALL GONE!