Freshwater Tiger Moray Eels 14-15" (Gymnothorax Polyuranodon)

What is a freshwater tiger moray eel?

The freshwater tiger moray eel, also known as Gymnothorax polyuranodon, is a species of eel that is native to the freshwater rivers and streams of Southeast Asia. They are known for their striking appearance, with a pattern of dark stripes on a light background, resembling the spots of a leopard. 

ARE THEY REALLY FRESHWATER?

There is only one record of an adult Tiger Moray Eel being found in full saltwater (Aquatropic 2022.) While Gymnothorax Polyuranodon can tolerate brackish water, it tends to prefer freshwater environments. This preference is primarily driven by the availability of food sources. Freshwater habitats offer a rich variety of prey, including small fish, crustaceans, and mollusks, which serve as the eel's main source of nutrition in the wild, however aquarists will not have a problem getting them to eat pellets and other things covered later in this care guide.

Gymnothorax Polyuranodon possesses certain physiological adaptations that enable it to survive in both freshwater and brackish water environments. One such adaptation is its ability to regulate its internal salt concentration. This eel species has specialized cells in its gills that actively transport salt ions, allowing it to maintain the necessary balance in different water conditions.

While it is primarily found in freshwater environments such as rivers, lakes, and swamps, it is also known to venture into brackish water habitats, which are a mix of freshwater and saltwater. This adaptability allows the eel to explore a wider range of ecosystems.

What size tank do freshwater tiger moray eels need? How many can I keep per tank?

Freshwater tiger moray eels can grow quite large, reaching lengths of up to 3 feet. Therefore, they require a spacious tank to accommodate their size. Tank size widely varies. They are rather slow growing, so time it takes time for them to outgrow their tanks. 

First, lets establish the different sizes they come in as.

Can I keep a Large Tiger Moray with a Small Tiger Moray?

Tiger Moray Eels are very peaceful fish. I have witnessed 3 foot specimens ignore 9-12" specimens completely while existing in the same ecosystems. I would not recommend this large of a size difference but a large and medium eel or large with extra large wouldn't be out of the question at all. 

Morays play well with each other generally and many can be kept in the same tank as long as size allows.

What should the water parameters be?

The water temperature should be kept between 75-82°F (24-28°C), with a pH level of 6.5-7.5. They are hardy fish that are pretty easy to keep. Once I had a heater go out and didn't notice for four days and they survived 50-60 degree water. Aeration is important for gill function and high oxygen levels in the water, so topwater surface agitation of some sort is recommended. 

What do freshwater tiger moray eels eat?

These eels are carnivorous and primarily feed on small fish, crustaceans, and other invertebrates. In captivity, they can be fed a diet of frozen or live foods such as shrimp, fish, and squid. They will also accept pellets. To hook them on pellets, hold feedings for a week and try. Repeat. They love fish store guppies and other feeder fish. They are not very picky and I have witnessed them eating algae wafers meant for plecos before. 

Can freshwater tiger moray eels be kept with other fish?

While freshwater tiger moray eels can be kept with certain species of fish, it is important to choose tank mates carefully. They are known to be aggressive towards smaller fish and may see them as potential prey. It is best to keep them with larger, more robust fish that can hold their own. Bichirs, other eels, such is other tiger morays or fire eels, oscars, pufferfish, florida gar are examples of suitable tank mates. 

Are freshwater tiger moray eels suitable for beginners?

Yes absolutely. They are extremely hardy fish and with proper aeration and water paramaters, they will thrive. The biggest mistakes a beginner aquarist can make have to do with poor water quality. These fish are hardy and will tolerate a wide range of water quality and even hold up better against ammonia and high nitrites/nitrates than most other fish.