Saltwater Fish
Blue Hamlet

Species Description…

Scientific Name: Hypoplectrus gemma
Common Name: Blue Hamlet
Species Group: Hamlet
Habitat: Reef Safe with Caution
Care Level: Intermediate
Temperament: Semi-aggressive
Diet Type: Carnivore
Role in Aquarium: Showpiece Fish
Max Fish Length: 5 (inches)
Min Aquarium Size: 50 (gallons)
Native Range: Western Atlantic, mainly in the Caribbean Sea
Hypoplectrus gemma - Blue Hamlet

Hypoplectrus gemma (Blue Hamlet)

Overview

  • Native to the tropical western Atlantic, particularly around the Caribbean and Gulf of Mexico.
  • Renowned for its deep sapphire-blue coloration, giving it a jewel-like appearance.
  • A relatively small but bold fish, often seen patrolling rocky crevices and coral structures.
  • Thrives in well-established reef tanks with plenty of hiding spots.

Feeding

  • Carnivorous diet, preying on small crustaceans and tiny fish in the wild.
  • Readily accepts frozen mysis shrimp, brine shrimp, and high-quality marine pellets.
  • Offering a varied diet enhances coloration and promotes active foraging behavior.
  • Requires one to two feedings per day to maintain energy levels.

Habitat

  • Commonly found in coral reefs, rocky overhangs, and areas with abundant hiding places.
  • Prefers aquariums with a mix of live rock, caves, and shaded regions to retreat when feeling threatened.
  • Moderate to low water currents replicate its natural reef habitat.
  • Appreciates stable conditions with high water clarity for optimal health.

Fish Care

  • Optimal water temperature: 74-80°F (23-27°C).
  • pH level: 8.1-8.4, with a specific gravity of 1.023-1.026.
  • Resilient but benefits from pristine water conditions and regular maintenance.
  • Best kept in an established tank with minimal fluctuations in water parameters.

Compatibility

  • Semi-aggressive; best housed with other assertive tank mates to avoid bullying.
  • May show territorial behavior, particularly toward similar-looking basslets or small fish.
  • Compatible with most reef-safe species, including clownfish, tangs, and wrasses.
  • Should not be housed with timid fish that may become targets of harassment.

Aquarium Behavior

  • Active and inquisitive, frequently patrolling its preferred rock formations.
  • Can be territorial if space is limited, making larger aquariums a better choice.
  • Displays interesting color shifts under different lighting conditions.
  • Providing an enriched environment with caves and hiding spots encourages natural behaviors.