The Smithsonian National Zoological Park [announced the death of two arapaima fish in a press release Monday](https://nationalzoo.si.edu/Publications/PressMaterials/PressReleases/NZP/2009/arapaima.cfm). The first fish died on Nov. 19, and the second fish died on Nov. 27. The arapaima had lived in the zoo’s Amazonia exhibit for 16 years, arriving in 1993.

Zoo staff said that the fish were about 17 years old, which is the typical life span of captive arapaima. According to the press release, a necropsy carried out after the death of the fish initially proved inconclusive, but a bacterial infection is now the suspected cause.

Zoo staff will be conducting further tests. There were no problems with the aquatic equipment in the tank, which could have caused the death of the fish, according to the press release. The tank is being observed closely by zoo staff, since a third arapaima is in poor health and is being treated with antibiotics.

The fish is responding to treatment, but its health continues to be monitored. A fourth adolescent arapaima appears to be in good condition, but is being given antibiotics as a precaution. Other species of fish kept in the tank appear to be in good health.

The arapaima is one of the largest freshwater fish in the world – its natural habitat is in the Amazon and Orinoco Basin in South America. This species of fish, known for its large scales, typically grows to become 6 to 7 feet long.”