Can Moray Eels Live in Freshwater?

It is amazing how many times we get email asking, can I put a saltwater eel into a freshwater or brackish aquarium? In particular this happens most often with the Snowflake species. This question arises because people see an Eel labeled as a "Freshwater Snowflake Moray" in a fish store, and because of the "Snowflake Moray" name they assume it is a true saltwater Snowflake Moray Eel acclimated to live in freshwater. Quite simply the answer to this question is NO, you cannot put a true saltwater Moray Eel of any kind into fresh or brackish water and expect it to live. They are just that, saltwater fish!! With all the research we have done about this, we are not aware of ANY "true" freshwater Moray Eels.

One of the first questions we ask an e-mailer when inquiring about this topic is, did the fish store provide a scientific or species name for the Eel they were selling? In all cases the answer was no. If the Eel that is being sold is not identified, then how do you know exactly what it is? And, without this information how are you supposed to care for it? Properly identifying an animal you are thinking of buying is essential to its well being. So, how do you identify a saltwater VS freshwater Snowflake Eel? Simple. The Echidna nebulosa (pictured) is a saltwater Snowflake Moray Eel. If you see this name attached to an Eel being sold as a "Freshwater Snowflake", it's most likely not one. It has either been grossly misrepresented or misidentified, and if in fact it is the saltwater species being kept in freshwater, how sad! 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), but they cannot remain permanently in these conditions without eventually perishing.

To further help clear up the confusion between saltwater and so-called freshwater Eels we consulted with Shirlie Sharpe, your About Freshwater Aquariums Guide. She provided the following information in response to an example of just one of the many e-mails we get on this topic:

"You are right, it's nonsense. There aren't any "true" freshwater Moray Eels. However, there are some freshwater Eels that may be misrepresented as such (you know how 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. For your info, all true freshwater Eels belong to the Family Anguillidae. There is 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."

As with many common name references, species identification can sometimes be difficult. To assist with the identification of freshwater Eels, as not to confuse them with saltwater species, here are some resources you can refer to:

• Freshwater Eel Profiles & Photos - A slow loading page, but includes an image of a White Spot Spiny Eel (Mastacembelus armatus), often mistaken or misidentified as a saltwater Snowflake Moray Eel.
• Fire Eel (Mastacemblus erythrotaenia) Profile & Photo
• Spiny Eel (Mastacembelus armatus/Macrognathus armatus) Profile

To learn more about the identification, characteristics and keeping of Eels, refer to our complete collection of Eel Care & Photo Resources.

Update: Since writing this article it has been brought to our attention that there are some "true" Moray Eels that do inhabit or can adapt to freshwater and/or brackish water environments. Refer to our Freshwater VS Saltwater Moray Eels Revisited article for more information about these Eels, how to identify them and what their primary water habitat preferences are!