Mastacembelus oatesii – Oates’ Spiny Eel (~37 cm / ~15″ max)

📦 Description

Mastacembelus oatesii is a spiny eel species native exclusively to Inle Lake in Myanmar. Males can reach up to approximately 37 cm in length and feature a broad, short snout with large dark spots along a slender body. It has fewer dorsal and anal fin rays compared to most Mastacembelus species—typically 48–56 dorsal rays and 46–60 anal rays, with correspondingly fewer vertebrae . Unlike many of its relatives, the fins are free of spot patterns and smoothly edged, giving it a clean, elegant appearance. Due to its highly localized habitat, captive husbandry is undocumented and challenges remain unknown.

🧰 Care Instructions

While no direct data exists for M. oatesii husbandry, other Mastacembelus species provide a useful guideline:

• Tank Size: Large setup (≥150 L / ~40 gal) with plenty of horizontal swimming room.

• Flow & Oxygenation: Moderate to low flow, but excellent oxygenation is essential.

• Water Parameters:

  • Temperature: 24–28 °C (75–82 °F)

  • pH: 6.5–7.5

  • Hardness: Soft to moderate

• Substrate & Decor: Fine sand with buried tunnels or PVC tubes for hiding. Provide caves and driftwood for shelter.

• Diet: Carnivorous bottom-feeder—offer earthworms, tubifex, bloodworms, freshwater crustaceans, and sinking carnivore pellets. Occasional live prey encourages activity 

• Behavior & Tankmates: Generally peaceful but may eat very small fish; best paired with larger, calm community species. Keep alone or in small conspecific groups if available.

• Maintenance: Stable water quality is crucial—weekly partial changes (20–30%), efficient biological filtration, and minimal temperature swings.