Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com. Could you explain how fish sleep? Do they drift ...

As a lifelong fishkeeper, I’m familiar with noisy fish. Perhaps my favorite noisy aquarium fish are the Synodontis catfishes, which produce a rasping sound resembling a growl that can easily be heard ...