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Zoo Vet Team's Latest Surgery Makes a Splash!

Zoo veterinarians conduct routine procedures on a wide array of exotic animals. While it's common to perform surgery on a big cat, repair the shell of a turtle, or conduct ultrasounds on a tapir, our team encounters some patients that are not so ordinary. Recently, our vet team conducted surgery on a most unusual patient– a three-foot long fish!

Keepers noticed a growth under the jaw of one of the oldest fish in the River Tanks at our Unseen New World exhibit. This black arowana (Osteoglossum ferreirai) has been in the collection for over 16 years in perfect health. So when the mass continued to grow, it was decided that surgical intervention was necessary.

Arowana are armor-plated, muscular fish known for their jumping ability, so the keepers had to carefully train her to accept being cradled in a net without becoming stressed. It took several weeks of training and acclimating her to the net so when the day of surgery arrived, she was calm and cooperative. After being immerserd in an anesthetic solution, the tumor was quickly and carefully removed and she was back to swimming in her tank in no time.

While the black arowana has made a full recovery and appears to be doing very well, keepers continue to closely monitor her for regrowth of the tumor. Veterinarians, technicians, and keepers all came together to perform this procedure on one of our most unusual patients!

Here, our vet team examines the mass on fish's underside.
After the procedure, the arowana was quickly returned to her tank.
After the tumor was removed, the wound was sealed with a thin coat of flexible protectant.
The fish rests comfortably in the mesh netting during the operation.
Posted by Nashville Zoo at 11:06 AM


1/4/2017 at 04:04 PM by Thalea

That is awesome!!!

1/4/2017 at 09:35 PM by Lisa Holyk

Very cool, just wish there was more info. How long was the fish out of the water? How was it kept alive during the surgery? Sounds like there was no anesthetic used. Do fish not process pain the same way? I would assume that if it was in pain, it would have been moving too much to operate.

1/5/2017 at 10:24 AM by Nashville Zoo

Hi Lisa! The black arowana was immersed in an anesthetic solution mixed in the water of the tank where her surgery took place. The anesthetic used is called Tricaine, which is the only USDA approved anesthetic agent in fish. They absorb it through their gills and recover quickly when placed into fresh water. The fish was only completely out of the water briefly, when moving between her tank and the anesthesia tank; otherwise she was kept partially submerged. At all times, a small pump was used to keep water flowing over her gills, and over her scales to keep her wet.

1/5/2017 at 08:18 PM by Lisa Holyk

Thank you so much for answering my questions. I see now where it says she was immersed in an anesthetic solution, but all the other details really helped me understand how it was done. Again, thanks.

1/8/2017 at 07:41 PM by Nichole Young

Was this the Nashville Zoo's first operation on a fish and was it the first operation on a water animal. Also what was the most difficult part of the procedure

1/15/2017 at 06:43 PM by Christi Gaskins

This is cool! I graduate from vet tech school may 6th. I would love to work at the zoo. Are there any jobs available even entry level?

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