Many people who have owned freshwater Morays contend that they are meant to be kept in a pure freshwater or pure saltwater environment. Neither of these statements is true. It is well documented by professional aquarists that freshwater Moray Eels are true brackish-water fish. This means that, while they can survive temporarily in pure fresh or pure saltwater environments, to live a long and healthy life they must be provided with brackish-water conditions.
Another common issue with these animals is that pet stores often sell pure saltwater varieties of Moray eels as freshwater varieties. It is essential that the aquarist makes sure he is purchasing a freshwater Moray, and not one of its oceanic cousins. Specifically, seek out the species Echidna rhodochilus and Gymnothorax tile.
General Information on Freshwater Moray Eels
Freshwater Moray Eels are typically found in tropical waters around Asia, including estuaries, river mouths, and other places where fresh and saltwater meet. As such, the temperature in their aquarium should be maintained between 78-82 degrees Fahrenheit (25-28 degrees Celsius).
Freshwater Morays are also fairly large, usually reaching lengths between 12 and 24 inches in length. Because of their size, they must be provided with a large aquarium (at least 30-55 gallons). They are also predatory in nature and will most likely prey on small fish and invertebrates. Despite their nature, they can be kept with other large, brackish-water fish without problems. Freshwater Morays can tolerate a range of salinity levels, but the specific gravity should remain stable and measure at least 1.005.
Housing Freshwater Morays
Large, brackish-water aquariums need to be provided to keep a freshwater Moray Eel healthy. They also require a soft, sandy substrate to move around on and possibly burrow in. Their skin is sensitive and overly coarse substrate can damage them. Any sharp objects or protruding edges should also be removed from the aquarium.
Freshwater Morays are also known for jumping out of aquariums. They can be easily spooked by loud noises and may become startled and jump. They will also naturally test the aquariums for places to slip out. For these reasons it is important that the aquarist provide a secure, sturdy lid to prevent any escape attempts. Any holes or gaps that the lid does not cover should be sealed.
Numerous hiding spots are essential for the well-being of the Moray. They are very sensitive to stress and prefer the security of aquarium caves and overhangs. Freshwater Morays are primarily nocturnal and will spend much of the day in hiding.
Feeding Freshwater Moray Eels
One of the greatest challenges of owning freshwater Morays is feeding them properly. Often times when a freshwater Moray Eel is first purchased, it will refuse to eat. Sometimes, if it is not provided the correct living conditions and foods to mitigate stress, the eel will starve to death. However, they can survive long periods without food. If they do not eat right away, do not be alarmed. Simply try and improve their living conditions and provide the proper foods to initiate their appetite.
Freshwater Moray Eels have a strong preference towards live foods, especially small fish and shrimp. They are also known to be fond of other small invertebrates such as crabs and crayfish. Eventually they can be weaned onto frozen foods such as clams, squid, shrimp, krill, and fish. They are very unlikely to accept packaged or prepared foods, and such foods would not be the healthiest option for them.
Freshwater Moray Eels are interesting and adaptable brackish-water fish, making for excellent community members, provided there are no small fish present. The primary concerns for the aquarist should be a stable brackish-water environment, reducing potential stress on the eel, and providing healthy, live foods for the Moray to prey upon. With these needs met, freshwater Moray Eels can be a captivating, low-maintenance specimen.
Source: Monks, Neale, ed. Brackish-Water Fishes: An Aquarist’s Guide to Identification, Care & Husbandry. 2006.
Aaron Guzman - Aaron Guzman currently lives in Eureka, California and works as a freelance writer. He spends his spare time writing fiction, playing ...
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