The most recent California Department of Fish and Game Q&A has an interesting item from a man who identified himself as a Buddhist.
“For expressing mercy we used to buy captive fishes and set them free in rivers,” the man, James W., wrote. “However, we could not buy live bred fishes and free them here because the salesperson in the supermarket said it violates California laws.
“I could not find any information in the regulations you issued. Please tell us which codes apply.”
DFG responds that many fish and game laws make it illegal for anyone without a stocking permit to release any fish into waters of the state, both freshwater and saltwater.
You can see why it’s a potential problem. There are about 260 invasive species in the Delta, fish and others. Someone thought it’d be a good idea to dump a few stripers in the drink near Martinez in 1879, and now we know that they eat baby salmon (though the extent of the predation, and its effect on salmon populations as a whole, is debated).
I don’t know much about Buddhism. I do know that Buddhists revere animals and avoid harming them in any way, with the understanding that all living things can feel pain. For a little insight, watch this YouTube video of the San Francisco Buddhist Fish Release of June 26, 2010. (The fish are released at about the five-minute mark.)