Delta Tail Guppy

The Delta Tail Guppy is one of the most iconic and visually striking guppy varieties, named after its large, triangular tail fin that resembles the Greek letter Δ (Delta). Known for elegance, symmetry, and vibrant coloration, the Delta Tail Guppy represents the pinnacle of selective guppy breeding and is a favorite among hobbyists, breeders, and show competitors worldwide.

Scientific Name: Poecilia reticulata
Common Name: Delta Tail Guppy
Difficulty Level: Easy
Category: Fancy Guppy

Appearance & Physical Characteristics

Tail (Caudal Fin)

• Shape: Wide triangular (delta-shaped)

• Spread Angle: Often close to 120–180 degrees

• Size: Can be as large as the body length in males

• Edges: Smooth or slightly rounded depending on strain

The tail is the defining feature and primary focus in show-quality Delta Tail Guppies.

Coloration & Patterns

Delta Tail Guppies come in an extraordinary range of colors and designs:

Solid Colors

• Red

• Blue

• Yellow

• White

• Black

• Green

Patterned Variants

• Mosaic Delta

• Cobra Delta

• Leopard Delta

• Grass Delta

• Tuxedo Delta

The large tail surface allows intricate patterns to appear bold, detailed, and artistic.

Body

• Streamlined and elegant

• Often metallic or half-black in certain strains

• Males are slimmer and more colorful

• Females are larger with shorter, rounded tails

Size

• Males: 3.5–4 cm (1.4–1.6 inches)

• Females: 5–6 cm (2–2.5 inches)

Behavior & Temperament

Delta Tail Guppies are peaceful, social, and highly active.

• Swim gracefully, displaying tails constantly

• Males perform frequent courtship displays

• Non-aggressive and community-safe

• Best kept in groups

Their slow, flowing movement makes them especially calming to watch.

Tank Requirements

Tank Size

• Minimum: 10 gallons (40 liters)

• Larger tanks recommended to prevent tail damage

Water Parameters

• Temperature: 22–28°C (72–82°F)

• pH: 6.8–7.8

• Hardness: Moderate (8–15 dGH)

Stable water conditions are crucial to maintain fin health.

Tank Setup

• Gentle filtration (strong currents can damage tails)

• Live plants like Java moss, guppy grass, hornwort

• Open swimming areas

• Smooth decorations (avoid sharp edges)

• Moderate lighting to enhance tail colors

Weekly water changes (20–30%) are highly recommended.

Diet & Feeding

Delta Tail Guppies are omnivorous and thrive on a varied diet.

Recommended Diet

• High-quality guppy flakes or micro pellets

• Live/Frozen foods:

  • Brine shrimp

  • Daphnia

  • Bloodworms (occasionally)

• Plant-based foods:

  • Spirulina flakes

  • Blanched vegetables

Feeding Schedule:
2–3 small feedings per day

A nutritious diet enhances tail size, symmetry, and color vibrancy.

Tank Mates

Suitable Tank Mates

• Other guppies

• Mollies and platies

• Tetras and rasboras

• Corydoras catfish

• Peaceful shrimp

Avoid

• Fin nippers (barbs, aggressive tetras)

• Large or aggressive fish

Delta tails are delicate and easily damaged.

Breeding & Genetics

Delta Tail Guppies are livebearers.

• Gestation period: 25–30 days

• Fry per birth: 20–60

Breeding Tips

• Maintain male:female ratio of 1:2 or 1:3

• Use breeding tanks for line purity

• Separate fry or provide dense plants

• Fry food:

  • Baby brine shrimp

  • Powdered flakes

Selective breeding is essential to maintain wide, symmetrical tails.

Health & Common Issues

Common Problems

• Fin rot (especially tail edges)

• Torn fins

• Ich (white spot disease)

• Stress-related fin clamping

Prevention

• Clean, stable water

• Gentle water flow

• Avoid sharp décor

• Quarantine new fish

Healthy Delta Tail Guppies display fully spread, flowing tails.

Lifespan

Average lifespan: 2–3 years

With excellent care and genetics, some may live slightly longer.