Floating goldfish, especially post-eating, is a common issue that results in an internet wormhole. Let’s get some facts straight about the anatomy and physiology behind floating goldfish:
Goldfish are Physostomous Fish
Yes, it’s a big word. What is means is that goldfish, like many other carp, have a pneumatic duct between their swim bladder and esophagus. It connects in between the cranial and caudal swim bladder.
WARNING: FOLLOWING PICTURE IS GRAPHIC
The pneumatic duct helps goldfish regulate their buoyancy by taking swallowed air and pumping it into the swim bladder. Goldfish are able to regulate their buoyancy by the amount of air that they swallow. Excess air is removed from the swim bladder via the Oval, which removes air by diffusing it into the bloodstream.
Goldfish Like to Eat
Many goldfish eat like ravenous Golden Retrievers, sucking in floating food at the surface. In doing so, they inadvertently suck in extra air, resulting in added volume to their swim bladder. This can be more common in tanks and ponds with lots of goldfish and a very small space to eat, leading to addition competition and a race to see who can get their fill the fastest. Additional air in the swim bladder results in a positively buoyant fish, aka a floaty fish.
Why Doesn’t This Happen to Every Goldfish?
Just like all people are built differently, some goldfish have better control of their buoyancy, don’t eat as fast or aren’t affected as much as other fish. Fancy goldfish, bred to be pretty, not structurally sound, usually have to sacrifice some of their swim bladder to make room for other organs. Some of these varieties are more prone to buoyancy disorders than standard goldfish.
How Do I Fix My Floating Goldfish?
Given some time, most goldfish are able to correct their floaty ways. Air is removed from the swim bladder via an oval gland. It does take a little bit of time to work. Resist the urge to “pop” your fish yourself. The biggest problem with a floating fish is that their skin is no longer underwater. Air ulcerations can start to form and damage your fish’s skin. If they are starting to dry out, take one clean finger and apply a light coating of triple antibiotic or neosporin. Your veterinarian may remove air surgically from your fish in order to correct serious cases.
Depending on the cause and severity of the buoyancy disorder, solutions may be temporary or long-term. For long-term floating goldfish, it is critical to keep their bodies moist. This can be done by spreading bubble wrap across 2/3 to 3/4 of the surface of your tank, allowing your filter to return normally and any aeration to also reach the surface. This way, when your fish has a floating event, the bubble wrap will help keep them partially submerged and protect their delicate skin from drying out.
How Do I Prevent Floating Goldfish from Happening?
According to the internet: feed green peas. Do you know why they work? No, it’s not the fiber content; it’s because they sink. A sinking diet prevents your fish from sucking in extra air during feeding. But peas don’t contain complete fish nutrition and should NEVER be the only thing in your fishes’ diet. What you need is a SINKING PELLET. Yes, they exist. Managing buoyancy disorders for some fish may be a complicated process. If you need help, ask your aquatic veterinarian, or have your local veterinarian consult with an aquatic vet.