* Loss of Muscle Control: When a fish dies, its muscles relax and it loses the ability to swim. This means it can no longer actively keep itself afloat.
* Gas Buoyancy: Fish have a gas-filled swim bladder that helps them control their buoyancy. When a fish dies, this bladder deflates, leading to a loss of buoyancy.
* Decomposition: As a fish decomposes, gases build up inside its body. These gases are usually released, which further contributes to sinking.
Important Note: It's crucial to remove a dead fish from an aquarium promptly. Decomposition can contaminate the water and harm other fish.