swim bladder disease

Swim bladder disease

Swim bladder disease

When I write articles for the blog, I generally get my ideas from one of four sources of inspiration:

  1. I try to think of a mistake I made in the past and write a post that would have helped me avoid making that mistake
  2. I pass on the information from something I’ve learned recently
  3. I write about something happening with my own aquarium

Well the post this week is about swim bladder disease, and unfortunately the inspiration is from my own tank.

Swim bladder

Swim bladder

What is a swim bladder?

Bony fish have an organ in their body that helps them stay buoyant and upright in the water. The organ is filled with gas and is called a swim bladder, glass bladder or air bladder. Cartilaginous fish, like sharks and rays, do not have swim bladders–but unfortunately, my female Amphiprion ocellaris (common clownfish) has a swim bladder and I think she may have swim bladder disease.

What is swim bladder disease?

Swim bladder disease is a term used to describe a sick or injured fish that is unable to hold itself upright or maintain its position in the water column. My clownfish have adopted a toadstool leather coral as their anemone surrogate, and that is where they have hung out for the past couple of years. But a few days ago, my female clownfish started showing signs of swim bladder disease.

What are the signs of swim bladder disease?

The most prominent sign of swim bladder disease is a fish that is unable to swim normally. The fish looks like it is having problems staying balanced, or upright in the water. Sometimes, fish with swim bladder disease seem to bob back and forth in the water, darting down and then bobbing back up. Other times they may just look like they’re laboring, or swimming really hard just to stay in place. For my clownfish, the signs were that she was no longer nesting in the leather coral and was lying on her side at the surface of the water. Every now and then it seems like she is rasping at the surface (trying to swallow air?). She is still eating. She rights herself and swims in the current of the return pump and then drifts back to lay on her side at the surface in the middle of the tank.

swim bladder disease

Image by L Church

What causes swim bladder disease?

Unfortunately, like a few of the maladies that affect saltwater aquarium fish, swim bladder disease does not appear to have one specific cause. There are a few theories:

  • Trauma/Injury
  • Bacterial infection
  • Parasitic infection
  • Stress/rapidly changing water parameters
  • Poor water quality

My water quality appears to be fine, but I’m going to do some water changes just to be extra cautious. I don’t believe there were any rapidly changing water parameters–and there were no major changes to the tank recently, so in my case, I’m narrowing the possibilities down to Trauma or infection. It’s hard for me to assess whether the trauma was the primary cause. My clownfish tend to squabble a bit, but I didn’t observe any out-of-the-ordinary fighting before I noticed my sick fish, but there is certainly a lot of fighting now. The male routinely swims up, shudders and takes a nip at a fin or tail.

How do you treat swim bladder disease?

Since swim bladder disease isn’t caused by just one thing, the first step in treating swim bladder disease is diagnosing what you think the primary cause is.

To treat a sick fish, be sure to remove it from the display tank and treat it in the quarantine/hospital tank. That will allow the fish to recover without being harassed by the other fish and enable you to medicate in a smaller, controlled environment.

If the fish is suffering from trauma, a little rest in relaxation in a hospital tank may be all that is needed.

Treat a bacterial infection with an antibiotic.

Treat parasites with copper or medication specifically labeled to kill parasites.

For rapidly changing water conditions, identify the problem causing the changes and eliminate it. Heat water before doing water changes, replace faulty heaters or equipment, fix the problem and do a water change.

The cure for poor water quality is water changes. Bacterial and Parasitic infections can be treated with aquarium pharmaceuticals (antibiotics for bacterial infections and an anti-parasitic agent for a parasitic infection).

Here’s to hoping your fish (and my fish) get better soon. Do you have any solutions? If you do, please let me know in a comment below.


    1. Author

      Hi Oliver, thanks for the comment/question. The only thing definitive I’ve read in Dr. Noga’s textbook, Fish Disease: Diagnosis and Treatment that there is a nematode Anguillicola that infects swim bladders, but I believe that to be a freshwater problem. I was using the term to more generally describe when the fish no longer has control of the swim bladder to maintain their position in the water column. Have you observed this or do you have experience here?

  1. How is your fish doing? I have a clown that has it and it seems to be stress related (i just got him and he had it when i got them, i was hoping i could nurse them back or just give the clown a nice home in my tank) I have no other fish and I’m keeping my water consistent. How long did it take your clown to get better?

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