Thalassoma jansenii

Datasheet

General Description

Jansen's wrasse, scientifically known as Thalassoma jansenii, belongs to the Labridae family. These fish are visually appealing both as juveniles and adults, with a notable change in appearance as they mature. They are known to grow rapidly and can outgrow typical home aquariums. Thalassoma species have a diverse diet range, from Artemia to larger invertebrates like snails, crustaceans, and sea urchins. These wrasses have the ability to crush larger crustaceans on rocks to consume them more easily.

Aquarium Suitability

Considered suitable for aquariums, Jansen's wrasse requires meticulous care due to their aggressive nature towards other fish species. These fish can pose a threat to smaller fish, crustaceans, worms, snails, and other invertebrates. Additionally, they may nibble at clams, including Tridacna species. Due to their territorial behavior, they demand a large aquarium when fully grown, making it challenging to accommodate them in home setups. It is essential to provide regular feeding, ample hiding spots, and sufficient space to minimize their aggressive tendencies.

Care and Hardiness

With a hardy nature, Jansen's wrasse thrives on a diet that needs to be varied and provided multiple times a day to match their high activity levels. These wrasses are known to be beneficial in removing parasites from other fish species, although they may not have a significant impact on large outbreaks of marine ich. Adequate hiding places and a spacious swimming area are crucial for their well-being, even though they do not necessarily require a sandy substrate to thrive.

Reef Suitability

Reef compatibility for Jansen's wrasse is marked as "reef safe with caution." Their aggressive temperament towards other species, coupled with their tendency to eat small invertebrates and potentially disturb clam species, requires careful consideration when integrating them into a reef environment.

Aquarium Setup

When setting up an aquarium for Jansen's wrasse, it is essential to include numerous hiding spots, such as live rocks, to accommodate their need for shelter. A well-sized tank of at least 800 liters is recommended due to their territorial behavior and space requirements. Ensuring a secure lid is crucial as these fish are known to jump out of open aquariums.

Behaviour

These wrasses are known for their aggressiveness towards other fish and the need for a spacious environment to thrive. They are active swimmers and possess a territorial nature, which should be considered when planning their tank mates.

Feeding and Diet

Jansen's wrasse requires a varied diet that includes larger crustaceans, other invertebrates, small crustaceans like krill and mysis, and zooplankton such as Cyclops and pods. Feeding should occur multiple times a day to match their high activity levels.

Habitat and Distribution

These wrasses are native to the Indo-West Pacific region, ranging from the Maldives to Fiji, northwards to southern Japan, and southwards to Lord Howe Island. They are commonly found in areas with diverse marine life, including a variety of invertebrates and small fish.