Saltwater Fish
Apolemichthys trimaculatus
Apolemichthys trimaculatus - Three-spot Angelfish

Apolemichthys trimaculatus (Three-spot Angelfish)

Species Description…

Scientific Name: Apolemichthys trimaculatus
Common Name: Three-spot Angelfish
Species Group: Angelfish
Habitat: Reef Safe with Caution
Care Level: Advanced
Temperament: Semi-aggressive
Diet Type: Omnivore
Role in Aquarium: Showpiece Fish
Max Fish Length: 10 (inches)
Min Aquarium Size: 125 (gallons)
Native Range: Indo-Pacific (East Africa to Fiji, north to Japan, south to Australia)

Overview

  • Native to the Indo-Pacific, found in coral reefs and deep lagoons with rich coral cover.
  • Easily identified by its bright yellow body, a distinct black marking above the eye, and a dark spot on the gill cover.
  • A semi-aggressive species known for its curious and territorial behavior.
  • Popular among marine aquarists due to its striking appearance and unique personality.
  • Requires a well-maintained aquarium with plenty of swimming space and rock structures.

Feeding

  • Omnivorous diet, feeding on sponge, algae, and small invertebrates in the wild.
  • Readily accepts a variety of foods, including marine flakes, pellets, and frozen foods such as mysis shrimp and krill.
  • Supplementing with sponge-based foods and vitamin-enriched meals helps maintain health and coloration.
  • Requires frequent small feedings throughout the day to meet its dietary needs.
  • Avoiding overly processed foods helps ensure long-term vitality and immune strength.

Habitat

  • Commonly found in deep reef slopes, rocky outcrops, and areas with abundant coral growth.
  • Prefers stable water conditions with moderate to strong water movement.
  • Aquarium setups should include live rock structures to mimic natural hiding spaces.
  • Thrives in large, well-established reef tanks with diverse marine life.
  • Providing caves and overhangs encourages natural behavior and reduces stress.

Fish Care

  • Ideal water temperature: 74-82°F (23-28°C) for maintaining vibrant coloration and activity.
  • pH range: 8.1-8.4, with a salinity level of 1.020-1.025 to support a healthy immune system.
  • Requires high water quality with effective filtration to prevent stress-related diseases.
  • Regular water changes and testing for ammonia and nitrate levels ensure a stable environment.
  • Providing a well-balanced diet and a stress-free setting enhances longevity.

Compatibility

  • Semi-aggressive, best housed with similarly sized or larger fish to prevent bullying.
  • Compatible with tangs, larger wrasses, and other angelfish with proper introduction.
  • Should not be housed with small, timid fish or slow-moving species that may be harassed.
  • May nip at coral polyps, making it a risky choice for reef aquariums.
  • Providing ample hiding spots and a well-structured tank setup minimizes aggression.

Aquarium Behavior

  • An active swimmer that patrols its territory throughout the day.
  • May become territorial towards new tank mates if introduced improperly.
  • Often seen grazing on algae-covered surfaces and inspecting rock crevices.
  • Providing a well-structured tank with rockwork and hiding spaces supports natural behaviors.
  • Can become more confident and engaging when housed in a properly maintained environment.