Longfin Leopard Danio – 3.5cm

The Longfin Leopard Danio is a lively, peaceful schooling fish with a distinctive spotted pattern and elegant extended fins.

A longfin variation of Danio rerio, this fish combines the hardiness and active behaviour of the classic Zebra Danio with attractive leopard-style spotting and flowing finnage. At approximately 3.5cm, these fish are already large enough to show strong patterning while still having some growing to do.

They are an excellent choice for active community aquariums and are particularly well suited to aquarists looking for a colourful, hardy schooling species.

At a Glance

Scientific Name: Danio rerio
Common Name: Longfin Leopard Danio
Current Size: Approximately 3.5cm
Adult Size: Approximately 4–6cm
Origin: South Asia
Temperament: Peaceful and active
Care Level: Easy
Diet: Omnivore
Temperature: Approximately 18–26°C
pH: Approximately 6.0–8.0
Water Hardness: Soft to moderately hard
Minimum Tank Size: Approximately 60–70L recommended
Swimming Level: Upper to mid levels
Social Behaviour: Schooling
Breeding: Egg scatterer

Fish Profile

Longfin Leopard Danios are a selectively bred form of Danio rerio, the same species as the familiar Zebra Danio.

They retain the energetic, social behaviour of standard Zebra Danios but display a spotted or broken-line pattern rather than strong horizontal stripes, along with noticeably extended fins.

Danio rerio naturally occurs across parts of South Asia including India, Pakistan, Bangladesh, Nepal and Myanmar, where it inhabits streams, canals, ponds and other freshwater environments.

In the aquarium, they are constantly active and spend much of their time swimming through the upper and middle parts of the tank.

Colour & Appearance

The Longfin Leopard Danio typically displays:

• dark blue to black leopard-style spots
• silver to golden body colour
• subtle iridescent highlights
• extended dorsal, anal and caudal fins
• a streamlined, active body shape

The pattern can vary between individual fish, with some showing more distinct spots and others displaying slightly broken or elongated markings.

Lighting, diet, background colour and overall fish health can all influence how strongly the colours appear.

Schooling Behaviour

Longfin Leopard Danios are highly social fish and should not be kept individually.

A group of at least 6 fish is recommended, although larger groups are even better.

When kept in a proper school, they generally display:

• more natural behaviour
• stronger colour
• reduced stress
• more confident swimming
• less tendency to bother other tank mates

Larger groups also create a much more impressive visual effect as the fish move together through the aquarium.

Australian aquarium retailers commonly recommend groups of five or more, with larger groups preferred.

Temperament & Behaviour

Longfin Leopard Danios are peaceful but extremely active.

They are generally suitable for community aquariums, although their energetic swimming style means they are best kept with fish that are comfortable around constant movement.

They are not usually aggressive, but they can sometimes chase one another as part of normal social behaviour.

Because of their extended fins, avoid keeping them with known fin-nipping species.

Suitable Tank Mates

Suitable companions may include:

• Tetras
• Rasboras
• Corydoras
• Bristlenose Catfish
• small peaceful loaches
• other Danios
• peaceful Gouramis
• suitable livebearers
• other active community fish

Avoid:

• large predatory fish
• highly aggressive cichlids
• persistent fin nippers
• very slow or timid fish that may be stressed by constant activity

Tank mates should also share similar temperature and water requirements.

Aquarium Setup

Longfin Leopard Danios appreciate an aquarium with plenty of open swimming space.

A suitable setup should include:

• open swimming areas
• live plants around the sides and rear
• gentle to moderate current
• good oxygenation
• secure aquarium lid
• reliable filtration

Plants, driftwood and other decorations can provide structure, but avoid filling the entire aquarium with dense décor because these fish need room to swim.

They are excellent jumpers, so a secure lid is strongly recommended.

Water Conditions

Longfin Leopard Danios are relatively adaptable and tolerate a broader range of conditions than many tropical aquarium fish.

A practical aquarium range is:

Temperature: 18–26°C
pH: Approximately 6.0–8.0
Hardness: Soft to moderately hard

FishBase lists Danio rerio at around 18–24°C, pH 6.0–8.0 and approximately 5–19 dH in its natural range.

This adaptability makes them suitable for many community aquariums, although stable water quality should always be prioritised over chasing exact numbers.

Feeding

Longfin Leopard Danios are omnivorous and generally easy to feed.

Offer a varied diet including:

• quality tropical flakes
• small pellets
• micro granules
• frozen brine shrimp
• daphnia
• bloodworm in moderation
• suitably sized live foods

They are enthusiastic feeders and usually take food readily from the surface and upper water column.

Small portions once or twice daily are generally sufficient.

Variety helps maintain strong colour, good condition and natural activity.

Growth & Adult Size

Fish supplied are approximately 3.5cm.

Adult Longfin Leopard Danios generally reach around 4–6cm depending on genetics, diet and conditions.

FishBase records standard Danio rerio at around 3.8cm standard length, while aquarium strains are often reported somewhat larger when total fin length is included.

Their relatively small adult size makes them suitable for modest community aquariums, but their activity level means swimming length is more important than simply tank volume.

Longfin Considerations

The extended fins are what make this variety especially attractive, but they also require a little extra care.

Avoid:

• fin-nipping tank mates
• sharp decorations
• cramped aquariums
• poor water quality

Good nutrition and clean water will help maintain healthy fin growth and appearance.

Breeding

Longfin Leopard Danios are egg-scattering fish.

When in breeding condition, females become noticeably fuller-bodied while males are generally slimmer and more streamlined.

During spawning, eggs are scattered among plants or over the substrate.

The adults provide no parental care and may eat both eggs and fry.

For breeding, a separate aquarium with fine-leaved plants, spawning mops or mesh over the bottom can help protect the eggs.

Once the adults are removed, eggs usually hatch relatively quickly, and the fry can initially be fed very small foods such as infusoria before moving onto baby brine shrimp and finely crushed prepared foods.

Is the Longfin Leopard Danio Right for You?

Longfin Leopard Danios are an excellent choice for aquarists wanting:

• a hardy schooling fish
• active community aquarium movement
• easy feeding
• attractive spotted patterning
• flowing fins
• a beginner-friendly species

They are especially well suited to planted community aquariums where there is plenty of open swimming space.

Their combination of hardiness, activity and distinctive appearance makes them one of the easiest schooling fish to recommend for a wide range of freshwater aquariums.

Quick Care Guide

Current Size: Approximately 3.5cm
Adult Size: Approximately 4–6cm
Tank Size: 60–70L+ recommended
Group Size: 6+ fish recommended
Temperature: 18–26°C
pH: 6.0–8.0
Temperament: Peaceful and active
Diet: Omnivore
Swimming Level: Upper to mid levels
Breeding: Egg scatterer
Difficulty: Easy

Important Information

Fish supplied are approximately 3.5cm unless otherwise stated.

Longfin Leopard Danios are schooling fish and should be kept in groups rather than individually.

Individual fish may vary naturally in spotting, colour intensity, fin length and body shape.

Actual fish received may differ slightly from photographs due to age, genetics, lighting, condition and natural individual variation.