Freshwater Tiger Moray eel MEDIUM

The Freshwater Tiger Moray Eel (Gymnothorax polyuranodon) is an intriguing and exotic species of eel found in Southeast Asia and parts of Australia. Despite its common name, this species is not a true freshwater eel and typically thrives in brackish or coastal waters. The species is popular among advanced aquarium hobbyists for its snake-like body and striking appearance, as well as its unique behavior.

Freshwater Tiger Moray Eels are distinguished by their long, slender, snake-like bodies, which can grow up to 24-36 inches (60-90 cm) in captivity, though they may reach up to 40 inches (100 cm) in the wild. Their bodies are adorned with a series of dark tiger-like stripes or blotches running along their pale or brownish background. This pattern is highly variable, giving each eel a unique look. Their head is typically broader than their body, with a pointed snout and sharp teeth, which they use to catch prey.

Tiger Moray Eels are predatory and primarily nocturnal, preferring to stay hidden during the day and becoming more active at night. They tend to be shy and reclusive, often hiding in crevices, rocks, or tunnels within the aquarium. While not overly aggressive toward tank mates of similar size, they may hunt smaller fish or invertebrates. They are also escape artists, so tanks must be securely covered to prevent them from slipping out.

In the wild, these eels are carnivorous, feeding on small fish, crustaceans, and invertebrates. In captivity, they thrive on a diet of:

• Live or frozen fish such as silversides, feeder fish, or pieces of shrimp
• Mollusks like mussels or clams
• Crustaceans, including crabs and shrimp It is important to feed them meaty, protein-rich foods to mimic their natural diet and keep them healthy. They may not immediately take to prepared foods, so offering live or frozen prey is essential.

• Tank Size: Due to their large size and activity level, Freshwater Tiger Moray Eels require a minimum tank size of 75-100 gallons for a single adult. Larger tanks are needed if they are housed with other fish.
• Water Conditions: Despite the “freshwater” in their name, these eels are most comfortable in brackish water, though they can tolerate freshwater for periods of time. They do best in a salinity range of 1.005 to 1.015 SG (specific gravity).
  • Temperature: 75-82°F (24-28°C)
  • pH: 7.0-8.0
  • Water Hardness: 10-25 dGH (moderately hard)
• Tank Setup: The tank should mimic their natural environment with plenty of hiding places created from rocks, driftwood, and PVC pipes or caves. Soft substrate is recommended to prevent injury to their delicate skin. Good water filtration and regular maintenance are crucial, as eels produce a fair amount of waste. Additionally, the tank needs a tight-fitting lid, as these eels are known for escaping if given the chance.

Freshwater Tiger Moray Eels should be kept with larger, non-aggressive species. Tank mates need to be of comparable size or slightly smaller but not small enough to be seen as prey. Suitable companions may include large, peaceful fish such as:

• Monos
• Scats
• Archerfish
• Large brackish water fish

Avoid housing them with smaller fish or invertebrates that they could easily eat. Additionally, due to their predatory nature, they may not be ideal in a community tank unless careful consideration is given to their tank mates.

Breeding Freshwater Tiger Moray Eels in captivity is extremely rare and not well-documented. In the wild, they likely migrate to coastal or brackish waters to spawn, which makes breeding in a home aquarium setting challenging due to their specific environmental needs and migratory behavior.

With proper care, Freshwater Tiger Moray Eels can live for 10-15 years in captivity, making them a long-term commitment for experienced fishkeepers.

• Water Salinity: While they are sold as “freshwater” eels, they thrive in brackish water, and long-term exposure to true freshwater conditions may negatively impact their health. Gradually acclimating them to brackish conditions is highly recommended.
• Escape Prevention: Eels are notorious for escaping, so make sure all tank openings are secure. Use a weighted lid or clamps if necessary.
• Feeding: They can be finicky eaters at first. Offering live or fresh prey can entice them to eat until they adjust to frozen or thawed options.

This exotic and fascinating eel is best suited for advanced hobbyists with experience in maintaining large tanks and specialized water conditions. They offer a unique presence in an aquarium but require careful attention to their diet, habitat, and security.

Would you like more tips on setting up a brackish tank or finding suitable companions for your Tiger Moray Eel?