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Siamese Spiny Eel (Macrognathus siamensis)

Common Names - Zig-Zag Eel

Siamese Spiny Eel

Macrognathus siamensis, also known as the Siamese Spiny Eel or Zig-Zag Eel, is a nocturnal fish known for its elongated body and distinctive coloration.

Overview

Macrognathus siamensis, commonly known as the Siamese Spiny Eel or Zig-Zag Eel, belongs to the Mastacembelidae family. Native to Southeast Asia, this species is distinguished by its elongated, snake-like body and zig-zag markings along its flanks. Reaching a size of 20-30 cm (8-12 inches) in captivity, the Siamese Spiny Eel is a fascinating addition to freshwater aquariums. Known for its nocturnal nature, this eel-like fish is generally peaceful but requires specific tank conditions and care to thrive.

Tank Requirements

The Siamese Spiny Eel requires a minimum tank size of 200 liters (50 gallons) to accommodate its active and exploratory nature. It thrives in water temperatures ranging from 22-28°C (72-82°F) with a pH level between 6.0-7.5 and general hardness (GH) of 5-15. The tank should be well-planted with plenty of hiding places, such as caves, driftwood, and rocks, to mimic its natural habitat and provide security. A sandy substrate is ideal as it allows the eel to burrow, which is a natural behavior. Ensure a secure tank lid, as these eels are known to escape through even the smallest gaps.

Feeding and Diet

Macrognathus siamensis is carnivorous and primarily feeds on live or frozen foods such as bloodworms, brine shrimp, and small crustaceans. In captivity, they can also be trained to accept high-quality sinking pellets and wafers designed for carnivorous species. Feeding should be done in the evening or after the tank lights are turned off to align with their nocturnal habits. Providing a varied diet ensures proper nutrition and helps maintain their health and vibrant coloration.

Care and Maintenance

Caring for the Siamese Spiny Eel requires maintaining stable water conditions with regular water changes (20-30% weekly) to keep the water quality high. Due to their sensitivity to poor water quality, a robust filtration system is essential. Macrognathus siamensis can be prone to parasitic infections, especially in tanks with suboptimal water conditions, so regular monitoring and maintenance are crucial. Handle with care during tank cleaning or rearrangements, as their delicate bodies can be easily injured.

Compatibility

The Siamese Spiny Eel is generally peaceful but may prey on very small fish or invertebrates that fit into its mouth. Ideal tank mates include medium-sized, non-aggressive species such as peaceful cichlids, larger tetras, and other community fish that share similar water requirements. Avoid housing them with very small fish or aggressive species that might outcompete them for food or cause stress.

Breeding

Breeding Macrognathus siamensis in captivity is extremely challenging and rarely achieved. They are egg scatterers, laying eggs among fine-leaved plants or within crevices. To induce breeding, a separate breeding tank with optimal water conditions and plenty of hiding spaces is necessary. Conditioning with high-quality live and frozen foods can help prepare the fish for spawning. However, due to the lack of documented success, breeding efforts are typically reserved for advanced aquarists with experience in breeding more demanding species.

Note: Unverified Information

This article is part of our freshwater aquarium fish catalog and is currently unverified. The information presented here has not yet been reviewed by a specialist. Please use this content as a general reference and verify details from additional sources before making any decisions related to fish care.