You’re probably wondering how can fish sing at any time of the day. Well, ask the people living in houseboats in the San Francisco Bay, who are used to hearing humming coming from the water every night, stopping in the early morning. I know, this sounds pretty scary, hearing things like this in the middle of the night, but researchers finally figured out what’s causing this!
Melatonin, the hormone that tells us when it’s time to sleep, is apparently causing plainfin midshipman fish to sing. The female midshipman fish only grunts when they show aggression, but the males that try to mate with them use their swim bladders to create weird noises. For the midshipman fish, the melatonin is actually just a reminder that it’s night time it seems, which would explain the noises that only appear at night since their bodies don’t produce it during the day.
Even with the people knowing it’s the fish making these sounds, and the reason behind that, it doesn’t mean it will stop. Maybe there are people out there who wouldn’t be bothered by this sort of thing, but hearing some weird type of humming in the middle of the night is definitely something that you don’t want to hear.