Why is my fish sinking and what can I do to help it stay afloat?

Well, darling, hate to break it to you, but fish aren't supposed to sink like a rock. It sounds like your fish might have a swim bladder issue, which can be caused by overfeeding, constipation, or even a bacterial infection. Try fasting your fish for a couple of days and then feeding them a cooked pea to help with digestion. If the problem persists, it might be time for a trip to the aquatic vet.