Fish & shrimp health guide
Swim Bladder Disorder
Also called SBD, buoyancy problems, floating or sinking
A fish floating at the top, sinking to the bottom, or swimming sideways or upside down.
TL;DR, Swim Bladder Disorder
Swim bladder disorder is a buoyancy problem, not one disease, so the fish floats, sinks, tips over or swims upside down while otherwise looking fine. In most planted-tank fish it comes from diet: constipation or gulped air from dry food pressing on the swim bladder. It is not contagious. Fasting for a couple of days, then feeding a little blanched deshelled pea or soaked food, fixes many cases. Deep-bodied fish like fancy shapes and gouramis and bettas get it most, and if an infection or injury is behind it, that needs treating instead.
What you see
The fish struggles to hold its position: floating at the surface, sinking and resting on the bottom, listing to one side, or swimming nose-down or upside down. Appetite and colour often stay normal, which is the clue it is buoyancy rather than a systemic illness.
What causes it
- Constipation from overfeeding or an all-dry-food diet
- Gulping air with floating pellets, common in bettas and gouramis
- A sudden temperature drop slowing digestion
- Less often, an internal infection, injury, or birth defect affecting the bladder
How to treat it
- Fast the fish for one to three days to clear the gut.
- Then feed a small piece of blanched, deshelled pea, or pre-soaked sinking food, to relieve constipation.
- Soak dry foods before feeding so they don't expand or carry air into the fish.
- Keep the temperature in the fish's proper range to aid digestion.
- If it persists with other symptoms, treat for the underlying infection instead of assuming diet.
Treatment safety in a planted tank
There is usually nothing to medicate, which is good news for a planted tank. Reach for antibacterials only if there are clear signs of infection alongside the buoyancy problem, and then prefer quarantine.
Prevent it
Feed a varied diet, don't overfeed, soak or use sinking foods for air-gulpers, and keep the temperature stable. Most swim bladder trouble is a feeding habit, not bad luck.
Easy to confuse with
Dropsy also affects how a fish sits in the water, but it comes with a swollen, pineconing body. A fish that is otherwise plump and healthy but can't stay level is far more likely a diet-driven swim bladder issue.
Species most at risk
Species that catch this most often, or that need a gentler treatment:
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Is swim bladder disorder contagious?
No. It is a buoyancy problem, usually from diet, not an infection you can catch between fish.
Does the pea trick really work?
For constipation-driven cases, often yes. Fast first, then feed a small piece of blanched, deshelled pea to help clear the gut.
My fish still can't swim level after a week, now what?
If fasting and diet changes don't help and there are other symptoms, an internal infection or injury may be the cause, which needs treating in its own right.