It’s not really an eel 😉
The electric eel lives in the rivers and swamps of South America. Even though it looks like an eel, the two aren’t related. The tail end of the electrical Eel makes out 4/5 of the length. It contains muscles specialized in making electrical impulses measured up to 600 Volt.
The clicks heard from the speakers in the aquarium are those electrical impulses, which the eel uses to navigate in total darkness. When the eel gets fed, it gives off powerful electrical impulses, which can be heard out loud on the speakers.
The electrical eel uses the powerful impulses to hunt and to defend itself.