The machine used in fish tanks that makes bubbles is called an air pump or air stone. It add oxygen to the water and keeps the oils from coating the tank.
Bubbles
Bubbles is a Yellow Tang fish.
Fish may develop bubbles on their head due to a condition called "emphysematosis," which is caused by a build-up of gas in their tissues. This can be triggered by factors such as poor water quality, stress, or infections.
they're called "lantern' fish so they pretty much do produce their own light
yes bubbles help bring air to the fish and keep the water moving
Yep, it's called milt.
they have an organ called a swim bladder. it is a buoyancy device
fish
Go to the store and ask for a "bubbler", literally just a little device that makes bubbles. The kind/quantity you need depends on the size of your tank & number of fish.
You are supposed to have bubbles in your fish tank or else your fish will die because they don't have enough oxygen.
Bubbles
Then your filter is not on.