
Blue Moon Danio
Devario xyrops
- Care level
- Specialist
- Adult size
- 6–7.7 cm
- Minimum tank
- 100 litres
- Temperature
- 18–26 °C
Species profile
Danio kerri
Common names: Blue Danio

Blue Danio is a small to medium schooling danio requiring a group, a secure lid, clean oxygen-rich water, and at least 72 litres.
An iridescent blue danio with fine gold longitudinal lines and clear to lightly coloured fins.
The blue body and narrow gold lines separate it from Zebra Danio and Pearl Danio.
Adult females are generally fuller-bodied and slightly larger. Mature males are usually slimmer and show stronger colour, especially during courtship.
Keep a group of at least 8 in an aquarium at least 80 cm long. Provide open swimming space, secure cover, efficient filtration, and moderate water movement.
Use plants, wood, and rounded stone around the margins while preserving a clear central swimming area.
Keep planting and hardscape around the margins so the school has cover without losing the open midwater space it uses most.
Blue Danio is a social, active schooling fish that should be maintained with its own kind. Most chasing is part of normal group interaction, but cramped quarters or a group that is too small can concentrate aggression.
Maintain at least 8, preferably 12 or more. A larger group produces more natural schooling and spreads chasing. Not truly territorial, although males may spar or defend short-lived display positions within the group.
Choose peaceful, similarly active fish that share the same temperature and water requirements. Very slow, timid, or long-finned tankmates may be stressed by constant movement or persistent feeding competition. Small shrimp and shrimplets may be eaten.
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Xilong XL-803D canister filter – up to 100 LAn external-filter option for the moderate-flow setup described above. The seller lists a 400 L/h pump and an aquarium capacity of up to 100 litres.
Check the volume of your actual aquarium and the needs of its complete stocking. Use the flow control or spray bar to avoid a concentrated current. A larger tank or a species requiring strong river flow needs a different filter selection.
Cut-to-fit aquarium filter media padA cut-to-fit pad for compatible filter compartments. The listing describes a sheet approximately 16 by 12 inches; check the offered variant and the space inside your filter.
The seller description varies between five and eight layers, so confirm the actual sheet before ordering. Keep the filter manufacturer’s media arrangement and avoid obstructing the flow.
Xinyou ceramic filter rings – 300 gA biological-media option for a filter with a suitable media basket. This listing is a 300 g pack of ceramic rings.
Check the ring size and available basket space. Installing new media does not make a new aquarium instantly cycled, and these rings do not replace routine water-quality checks.
Keep the water clean and oxygen-rich. Soft to moderately hard water is preferable, with no sudden chemistry changes.
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Manual aquarium siphon and gravel cleanerA manual siphon for routine aquarium water changes and accessible waste removal. The seller lists a hose approximately 1.6 m long.
Control the flow and keep the intake clear of fish and delicate planting. Clean the areas appropriate for your substrate and layout rather than disturbing the entire planted bed.
An active danio from fast streams that feeds near the surface. Flake and small frozen foods suit it.
Feed small portions once or twice daily. Active danios feed quickly, so check that slower tankmates receive food.
An egg-scattering spawner with no parental care. Condition adults well, then use fine-leaved plants, spawning mops, mesh, or marbles to protect eggs from the adults. Remove the breeders after spawning and raise the fry on infusoria or very fine prepared food before moving to microworms and Artemia nauplii. For uncommon species, keep detailed notes on temperature, timing, adult condition, and fry growth because dependable species-specific aquarium reports may be limited.
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