Yellowtail Blue Damsel

Also known as Blue Damselfish, Blue Devil Damselfish.
The Yellowtail Blue Damsel is a small, vibrantly colored reef fish famous for its electric blue body and contrasting bright yellow tail. Native to shallow coral reefs and lagoons of the western Pacific, including the Philippines, Indonesia, and New Guinea, it is hardy, easy to care for, and generally peaceful in community aquariums. While adults may show mild territorial behavior, its manageable size and vivid coloration make it a popular choice for beginner and intermediate hobbyists looking to add a striking accent to marine tanks.

Key Features

• Scientific Name: Chrysiptera parasema
• Common Names: Yellowtail Blue Damsel, Blue Damselfish, Blue Devil Damselfish
• Adult Size: 2.5–3 inches (≈ 6–8 cm)
• Lifespan: 4–6+ years with proper care
• Temperament: Semi-aggressive — generally peaceful when young or in sufficient space, may defend territory in small tanks
• Reef Compatibility: Reef-safe; rarely harms corals or rockwork, but very small invertebrates may need monitoring
• Minimum Tank Size: 20 gallons (≈ 75 liters) for a single fish; larger tanks recommended for groups or community setups
• Experience Level: Beginner to Intermediate — hardy and easy to feed, thrives with stable water conditions

Habitat & Tank Requirements

Natural Habitat: Found in shallow reefs and lagoons of the western Pacific. Prefers coral and rocky outcrops where it can hide and graze.

Tank Environment:

• Provide live rock with crevices, caves, and overhangs for hiding spots
• Leave open swimming areas as they are moderately active
• Moderate water flow with efficient filtration
• Introduce only to mature, well-cycled aquariums

Recommended Water Parameters:

• Temperature: 72–78 °F (22–26 °C)
• Salinity: 1.020–1.025 sg
• pH: 8.1–8.4

Diet & Feeding

Yellowtail Blue Damsel is omnivorous and accepts both plant and animal matter.

Recommended Foods:

• Marine flakes or pellets for omnivores
• Frozen or live foods: mysis shrimp, brine shrimp, planktonic crustaceans
• Occasional algae-based foods or spirulina to support color and nutrition
  Feeding Schedule: Feed once or twice daily, giving only what they can consume quickly to maintain water quality

Behavior & Compatibility

• Juveniles are peaceful and adapt well to community tanks
• Adults may become semi-territorial, especially in small or crowded tanks
• Best kept singly or with peaceful, sturdy tank mates
• Avoid very small or timid fish that may be harassed
  

Suitable Tank Mates:

• Peaceful or semi-aggressive reef fish such as clownfish, gobies, and wrasses
• Reef-safe invertebrates usually compatible
• Avoid multiple damselfish in small tanks to reduce aggression

Reef Compatibility

• Generally reef-safe
• Rarely harms corals or disturbs rockwork
• Thrives in mixed reef setups when adequate space and hiding spots are provided

Acclimation & Care Tips

• Introduce only to stable, mature tanks
• Provide live rock or similar hiding places from the start
• Maintain stable water parameters (temperature, salinity, pH)
• Feed small, frequent meals rather than infrequent large feedings
• Monitor behavior with other damselfish and adjust space if aggression occurs

Signs of a Healthy Specimen

• Actively swims and explores the tank
• Bright electric blue body with vivid yellow tail
• Eagerly accepts flakes, pellets, frozen, or live foods
• Fins and body intact, no damage
• Clear eyes and normal respiration

Color & Development

• Electric blue body with a bright yellow tail
• Adults maintain compact size (≈ 2.5–3 inches) with vivid coloration
• Color intensity can vary slightly with age or environment

Special Considerations

• May show mild territorial behavior with age or in small tanks
• Stable water quality is essential for long-term health and color retention
• Widely available and popular in the aquarium trade

Breeding Potential

Yellowtail Blue Damsels are egg-layers that form pairs in the wild. Males display bright colors to attract females, who lay eggs on flat rock surfaces. Males guard and fan the eggs until hatching. Captive breeding is uncommon and requires stable water, quiet conditions, and sufficient tank space.

Why Choose a Quarantined Yellowtail Blue Damsel?

A quarantined Yellowtail Blue Damsel arrives healthy, free of parasites, and acclimated to aquarium conditions. Quarantine includes health observation, dietary conditioning, and gradual acclimation. This ensures a strong, stress-free fish that adapts quickly, displays vibrant colors, and integrates well into reef or FOWLR aquariums.