Thai Buddhists have believed for a long time that they will make good merit if they release fish and birds at a temple. The idea is that you are doing good by giving a creature its freedom. However, its often a short-found freedom as these creatures are often re-captured to only be sold again to the next person who arrives at the temple. The original idea behind releasing fish was to help those creatures left stranded in rice fields after the waters had receded from a flood. Villagers would save the lives of the fish by releasing them into a nearby canal or river.