By swimming around and such
Anything they eat - plants or other animals.
Fish use density in order to move in the water since they do not have lungs. When the density of water keeps changing, fish use it to move and thereby using less energy.
For a fish tank, it is recommended to use LED bulbs as they provide the necessary light for the fish and plants while being energy-efficient and long-lasting.
From the food they consume.
they get their energy from fish
energy is tranferred from insects to fish in this system by?
The energy for the plants in a fish tank is supplied by Light.
they already normally have when they are born
fish food for goldfish
They eat other fish.
One way is that we get sun energy from the fish we eat which they get the energy from another fish which they get energy from plants also they provide us vitamin D.
To breath by extracting oxygen from the water.