Breeding Eurasian Minnow

How to breed Phoxinus phoxinus: a gravel egg-scatterer that spawns in late spring over clean gravel in flowing, well-oxygenated water, with vivid breeding males.

Overview

The Eurasian Minnow (Phoxinus phoxinus) is a schooling river cyprinid of cool waters, occurring in streams at 12-20 degrees C (54-68 degrees F) and well-oxygenated lakes and ponds. It is a gravel egg-scatterer that spawns in late spring, with males developing strong nuptial colours.

Sexing

Breeding males intensify their contrast so that dark areas darken and light areas lighten; the fins, throat and some other areas redden, while the gills become very pale with iridescent light-blue patches towards the bottom. Scales on the lower body stand out and become slightly gold-lined, and all the fins, especially the dorsal, become more prominent. Females simply deepen toward the abdomen as they fill with eggs.

Breeding Setup

The species requires clean gravel areas in well-oxygenated flowing water, or where waves wash on lake shores. A cool, well-oxygenated tank with a current and a clean gravel bed reproduces these spawning conditions for this schooling fish.

Spawning Behavior & Trigger

Breeding begins around late May when the fish become noticeably more active. The males chase the females, rubbing their sides against them in an increasingly frenzied and aggressive courtship that culminates in spawning over the gravel.

Egg & Fry Care

Fertilised eggs promptly sink to the bottom and into the gravel, which shelters them from the current. The male then ferociously guards the eggs for a period of time, providing brief parental protection during incubation.