The Blue Danio is one of the most visually striking nano fish available and one of the most overlooked. Their iridescent blue sides with gold horizontal lines pop dramatically against dark substrate and dense planting. They're hardy, peaceful, and easy to care for — a fantastic choice for community tanks and planted setups alike.
Quick Stats
2"Max Size
15 galMin Tank Size
5–8 yrsLifespan
6+Min School Size
Water Parameters
| Parameter |
Ideal Range |
Notes |
| Temperature |
70–78°F |
Slightly cooler than most tropicals; stable temp important |
| pH |
6.5–7.5 |
Slightly acidic to neutral preferred |
| Hardness (GH) |
6–16 dGH |
Adaptable; soft to moderately hard |
| Ammonia / Nitrite |
0 ppm |
Cycled tank required |
| Nitrate |
<20 ppm |
Weekly water changes to keep low |
Tank Setup
Blue Danios originate from clear, slow-moving streams and floodplains of the Malay Peninsula and southern Thailand. They appreciate good water movement and oxygenation, a dark substrate, and both open swimming space and planted cover.
Tank size — 15 gallons minimum for a school of 6. A longer tank is better than a tall one — they're active swimmers and appreciate the horizontal space.
Plants — Dense planting enhances their coloration significantly. Hardy species like anubias, java fern, bolbitis, and microsorum work well attached to driftwood and rock. Floating plants help diffuse light.
Substrate — Dark sand or fine gravel strongly recommended. Their blue coloring appears paler over light substrate.
Flow — Moderate. They enjoy swimming against a gentle current. A HOB or canister with some flow works well — they'll actively play in the current near filter outlets.
Lighting — Moderate, not too bright. Dark substrate and dim lighting bring out their best color.
Lid — Required. Danios jump.
Diet & Feeding
Blue Danios are omnivores and unfussy eaters. They feed primarily in the middle and upper water column. A varied diet keeps their coloring vibrant and their immune system strong.
Staple: High-quality tropical flakes or small pellets
Protein: Frozen or live foods — baby brine shrimp, daphnia, micro worms, bloodworms
Frequency: Twice daily in small amounts — only what they can eat in 2–3 minutes
Remove uneaten food to maintain water quality
Temperament & Tank Mates
Blue Danios are peaceful, active schoolers. They do best in groups of 6 or more — smaller groups lead to stress and dull coloring. They occupy the middle water column and get along well with most community fish of similar size and temperament.
Good tank mates: Small tetras, rasboras, corydoras, otocinclus, other peaceful community fish of similar size
Avoid: Fish large enough to eat them, aggressive species, or slow-moving fish with elaborate finnage — Blue Danios can be nippy with delicate fins
Sexing: Males are slimmer and more colorful. Females are larger and noticeably rounder when conditioned for spawning.
Shrimp Compatibility
Generally compatible with adult shrimp. Blue Danios are peaceful enough to coexist with adult Neocaridina and Caridina shrimp in a well-planted tank. However, they will prey on shrimplets and baby shrimp. If maintaining a breeding shrimp colony alongside Blue Danios, provide dense moss, java fern, and plenty of cover to give juvenile shrimp places to hide.
Breeding
Blue Danios are easy to breed and will often spawn in a community tank without any setup — though fry survival in a community setting is low without intervention. A separate breeding tank significantly improves results.
Trigger — Spawning is often triggered by morning sunlight hitting the tank glass. Raise the temperature slightly to the higher end of their range to encourage breeding behavior.
Breeding tank — A shallow tank with a marble or large-pebble substrate (so eggs fall between gaps and out of reach of adults) and clumps of java moss. Keep it long and shallow.
Spawning — Females scatter up to 400 eggs. Remove adults immediately after spawning — they will eat the eggs without hesitation.
Fry — Eggs hatch in 2–3 days. Feed infusoria or powdered fry food first, then transition to baby brine shrimp as they grow.
Blue Danios are sometimes called Turquoise Danios or Splendid Danios. Under the right conditions — dark substrate, dim lighting, and dense planting — their electric blue coloring is genuinely striking and worth showing off.
Browse our aquatic plants to build the planted setup Blue Danios thrive in, or check our food and supplements for feeding options.
