Are you considering adding a freshwater tiger moray eel (Gymnothorax polyuranodon) to your aquarium? These fascinating creatures can make a unique addition to your tank, but they require specific care to thrive. In this FAQ care sheet, we'll answer some common questions about caring for freshwater tiger moray eels.
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?
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.
First, lets establish the different sizes they come in as.
| SMALL VARIETY | About the smallest they come in the trade, 6-11". Dull colors that later turn into gorgeous bright colors. |
| MEDIUM VARIETY | 15-16". These are much fatter, and taller, than their smaller counterparts. |
| LARGE | 20-23". Getting into terror territory. These fish are aggressive and love to hunt small goldfish and crayfish. |
| EXTRA LARGE | 29"+ Downright Scary. These are the kings of the tank. They will soar across the side of the glass. It's truly a crazy image. |
| Tank Size | Moray Eels That Can Be Kept |
| 20-29 Gallons |
2 Small Tiger Moray Eels Temporarily |
| 40 Gallons |
3 Small Tiger Moray Eels OR 3 Medium Tiger Moray Eels |
| 55 Gallons (this is where the fun begins) |
7-8 Small Tiger Moray Eels OR 5-6 Medium Tiger Moray Eels |
| 75 Gallons |
10+ Small Tiger Moray Eels OR 7-8 Medium Tiger Moray Eels OR 1 Large Tiger Moray Eels |
| 125 Gallons |
2-3 Large Tiger Morays OR 1-2 XL Tiger Morays |
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. Additionally, a good filtration system is necessary to keep the water clean and free from toxins. Good aeration is important as well. I recommend the use of a three part filtration system: Live Plants for Aeration and Water Parameter balance, A Mechanical Filter, such as a HOB Filter or Canister Filter, and a sponge filter for topwater agitation for oxygenation of the water.
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 picky, here is an image of one I had that was trying to eat an algae wafer.
Do freshwater tiger moray eels require any special hiding spots?
Yes, freshwater tiger moray eels are nocturnal and like to hide during the day. It is important to provide them with plenty of hiding spots in the form of caves, PVC pipes, or other suitable structures. These hiding spots will help them feel secure and reduce stress. All will cruise the tank exploring and being social.
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, and oscars 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 will even hold up better against ammonia and high nitrites/nitrates than most other fish.
In conclusion
Freshwater tiger moray eels can be a captivating addition to a well-maintained aquarium. It is crucial to provide them with suitable hiding spots and choose tank mates wisely. If you are an aquarist looking for a unique species, the freshwater tiger moray eel may be the perfect choice for you.