Tropheus polli Breeding Guide

Breeding Tropheus polli, a larger elongate Tanganyikan grazer: sexing, colony husbandry, maternal mouthbrooding and a strict herbivorous bloat-safe diet.

Overview

Tropheus polli is a larger, more elongate Tropheus endemic to Lake Tanganyika, known from the central eastern coast in areas with rocky substrates and reaching a total length of about 16.5 cm (Wikipedia). It is considered by some authorities to be a synonym of Tropheus annectens. As a genus member it is an algal grazer and a maternal mouthbrooder; detailed species spawning data is limited, so the genus pattern is used below.

Sexing

Sexes are hard to distinguish in Tropheus, which differ little in colour; venting (pointed papilla in males, rounded in females) or watching spawning roles in the colony is the practical method. The record notes a grey body with vertical bars and yellow blotches developing in males.

Conditioning

Provide a strictly herbivorous diet based on spirulina flakes and blanched greens, avoiding animal protein as advised for the genus. Recorded parameters are a temperature of 24-27 C, pH 8.5-9.2 and GH 12-25 dGH; stable hard, alkaline water supports conditioning.

Breeding Setup

Keep as a colony to disperse aggression; the record indicates a minimum school size of about 10 and a minimum tank of 450 L, larger than smaller Tropheus owing to this species' greater adult size. Rockwork over sand reproduces the natural biotope.

Spawning Behavior & Trigger

As a maternal mouthbrooder the female collects the eggs into her mouth, where the male fertilises them in the typical Tropheus sequence. A stable, well-fed colony in hard alkaline water is the main spawning trigger.

Egg & Fry Care

In keeping with the genus, broods are small and the fry comparatively large; the female holds them orally for several weeks before releasing free-swimming young that accept brine shrimp nauplii and powdered foods. Isolating a holding female protects the limited brood.

Common Challenges

Susceptibility to 'bloat' on incorrect feeding makes the herbivorous diet and clean water non-negotiable, and the aggressive temperament noted in the record means a large colony and ample tank are needed to breed this species reliably.