piscicide
/ˈpiskɪsaɪd/ or /ˈpɪskɪsaɪd/Definitions
1. noun
A substance or agent that is used to kill or control fish, especially in aquatic environments.
“The use of piscicides in the lake led to a significant decline in the local fish population.”
2. verb
To kill or control fish, especially in aquatic environments, using a substance or agent.
“The fishermen had to piscicide the invasive species in the river to protect the native ecosystem.”