Long-fin Zebra Danio (Danio rerio) Breeding Guide
Breeding the long-finned zebra danio: standard Danio rerio egg-scattering method, sexing, a dim egg-trap spawning tank and fry rearing.
Overview
The long-fin zebra danio is a selectively bred long-finned form of Danio rerio, with breeding biology identical to the standard fish. Seriously Fish describes the zebra danio as an excellent choice for first-time breeders and an egg-scattering spawner with no parental care; well-conditioned fish in mature, densely planted tanks may spawn spontaneously with some fry surviving naturally.
Sexing
Females are typically rounder-bellied, slightly less colourful and a little larger than males, with the difference especially clear in spawning condition as males intensify in colour and females fill with eggs (Seriously Fish). The trailing fins of the long-fin form make pairs slower swimmers but do not change sexing cues.
Conditioning
Condition adults together, then introduce one or two pairs to each breeding container once the females are full of eggs (Seriously Fish).
Breeding Setup
- Smaller breeding tank half-filled and very dimly lit, with a mesh (eggs pass but adults cannot), plastic grass matting or dense Java moss base (Seriously Fish).
- Slightly acidic to neutral water, towards the upper part of the 18-25 C maintenance range.
- A small power filter directing flow along the tank length, replaced with a mature sponge filter after spawning to prevent fry being drawn in.
Spawning Behavior & Trigger
Trigger spawning by adding small amounts of cool water every few hours while feeding small live and frozen foods; pairs typically spawn the following morning, scattering eggs over the base (Seriously Fish).
Egg & Fry Care
Adults consume the eggs and are best removed after a couple of days. Incubation takes about 24-36 hours before the fry become free-swimming days later. First food is Paramecium or a 5-50 micron proprietary dry food, progressing to Artemia nauplii and microworm as the fry grow (Seriously Fish).
Common Challenges
The main challenge is egg predation, handled with an egg trap and prompt adult removal. The long-fin trait is selectively bred, so fin quality varies in the offspring and the slower-swimming adults should be protected from fin-nipping tankmates during conditioning.