Can Moray Eels Live in Freshwater?

There is considerable confusion about whether moray eels can survive in freshwater. This confusion arises when people encounter an eel labeled as "Freshwater Snowflake Moray" in fish stores. The assumption is made that it is a true saltwater Snowflake Moray Eel adapted to live in freshwater.

"Freshwater" Eel

Simply put, the answer is no. A true saltwater moray eel cannot survive in fresh or brackish water. Based on all our research, there are no "true" freshwater moray eels.

If the eel being sold is not properly identified, how are you supposed to care for it? Proper identification of an animal you're considering buying is essential for its well-being.

How do you identify a saltwater or freshwater Snowflake Eel? It's simple. The Echidna nebulosa is a saltwater Snowflake Moray Eel. If you find this name on an eel being sold as a "Freshwater Snowflake," it's likely misrepresented or misidentified.

Saltwater fish can tolerate the lowering of salinity for short periods of time, which is often done for treating saltwater Ich by means of O.S.T. (Osmotic Shock Therapy). However, they cannot permanently survive in these conditions.

Some Guidance From Shirlie Sharp

To help clarify the confusion between saltwater and supposed freshwater eels, we consulted with Shirlie Sharpe. She responded to one of the many emails we receive on this topic: "You're right; it's nonsense. There aren't any "true" freshwater moray eels. However, some freshwater eels may be misrepresented in this way some pet shops are, they can mislabel a goldfish! In fact, I saw one myself. It looked vaguely like a Snowflake Eel, and the pet shop had a big sign on it "Freshwater Snowflake". In reality, it was a Spiny Eel, Mastocembelus armatus, which is not a true Eel at all. All true freshwater Eels belong to the Family Anguillidae. There's only one freshwater Eel indigenous to the United States: Anguilla rostrata or American Eel (unique name, huh?) What I've seen most often in shops are fish that are called Eels, but in reality, they are not from the Eel Family at all. Among them are "Fire Eels" (Mastacembelus erythrotaenia), "Tiretrack Eels" (Mastacembelus argus), or "Peacock Eels" (Macrognathus aculeatus). None of these fish are true Eels, and they are definitely not from the saltwater Moray Eel Family."

Identifying Fish By Name

As with many common name references, species identification can be challenging. To help identify freshwater eels and avoid confusing them with saltwater species, here are some resources:

• Freshwater Eel
• Fire Eel (Mastacemblus erythrotaenia)
• Spiny Eel (Mastacembelus armatus/Macrognathus armatus)

Update: Since writing this article, it has come to our attention that there are some "true" moray eels that can inhabit or adapt to freshwater and/or brackish water environments.