Rope Fish Breeding Guide

What is known about reproduction in the rope fish (Erpetoichthys calabaricus): anal-fin egg transfer and larval development, and why it has not been raised to adulthood in captivity.

Overview

Erpetoichthys calabaricus is an elongated, air-breathing fish from West and Central Africa. Spawning and hatching have been observed in captivity, but it has not yet been successfully bred to adulthood, and all aquarium fish are wild-caught.

Sexing

Males and females reach similar lengths, but females average heavier at a given length and the sexes can be reliably separated by the shape of the anal fin. Males tend toward olive-green colouring while females are more yellowish-brown.

Spawning Behavior

Females repeatedly deposit small batches of eggs between the anal fins of the male, where they are fertilised. The male then disperses the eggs among aquatic vegetation, to which they adhere.

Egg & Fry Care

Larvae hatch within roughly 70 hours and remain attached to vegetation. They become independent and begin to feed after about 22 days, once the yolk sac has been consumed. Carrying these fry through to adulthood has so far not been achieved in the aquarium.

Common Challenges

The barrier is not spawning but rearing: hatchlings have not been brought to adulthood under aquarium conditions, which is why the trade still depends on wild-caught fish.