Breeding the Tire Track Eel (Mastacembelus armatus)

Mastacembelus armatus spawns under rocky substrates during the monsoon; there are no known successful captive breeding programs, so home breeding is impractical.

Overview

The Tire Track Eel (Mastacembelus armatus) is a large Asian spiny eel of riverine systems across the Indian subcontinent, Sri Lanka, southern China and mainland Southeast Asia. It can reach up to about 91 cm in the wild, though it usually does not exceed 51 cm in captivity, and is a nocturnal carnivore that swallows prey whole. Globally it is listed Least Concern by the IUCN, though regionally threatened in parts of its range (Wikipedia; FishBase).

Sexing

According to species accounts, mature females are normally plumper than males, but the distinction only becomes apparent at sexual maturity (Wikipedia). No other reliable external cue is documented.

Conditioning

As a large nocturnal carnivore taking small fish, insect larvae, mollusks, crustaceans and annelids (Wikipedia), conditioning means a varied meaty diet over a sand bed in a very large tank. The natural reproductive cycle is tied to the monsoon, so a simulated wet season would be the conditioning endpoint.

Spawning Behavior & Trigger

The species spawns underneath rocky substrates during the monsoon season in nature (Wikipedia). The wet-season flood and associated changes in temperature and water chemistry are the natural trigger; the fish is noted to have relatively low fecundity, which leaves wild stocks vulnerable to overfishing (Wikipedia).

Egg & Fry Care

Eggs are deposited beneath rocky substrate during the monsoon (Wikipedia). Because there are no documented successful captive spawnings, detailed incubation and fry-rearing data for aquaria are not available and are omitted here rather than estimated.

Common Challenges

The decisive obstacle is that captive breeding has not been achieved, compounded by the species' large size, the need for monsoon-scale environmental change and the difficulty of sexing the fish reliably. This is not a realistic home-breeding project.