The Rainbow Blunthead Wrasse (Thalassoma amblycephalum) is a stunning, high-energy fish. However, being a member of the Thalassoma genus, it behaves very differently from the peaceful Fairy Wrasses you might be used to.

Reef Safe: With Caution. While they are "coral safe" (they won't eat your corals), they are not "clean-up crew safe." As they mature, they will readily feast on ornamental shrimp, small crabs, and snails. They are also known to be "tank decorators," occasionally flipping small unattached coral frags while searching for food.

Aggression: Semi-aggressive. Male Bluntheads are highly territorial and very fast swimmers. They can intimidate shy or slow-moving tank mates (like Firefish or Mandarins) simply by out-competing them for food. They should generally be the only Thalassoma wrasse in the tank.

Difficulty of Care: Easy/Moderate. They are incredibly hardy and disease-resistant compared to other wrasses. The main challenge is their metabolism; they are constant motion machines and require feeding at least 2–3 times a day. You must also have a very secure lid, as they are powerful jumpers.

Adult Sizing: Approximately 15 cm. While not a giant, their constant swimming means they require much more horizontal space than a sedentary fish of the same size.

Key Considerations for the Blunthead
Swimming Space: Because they are "open water" hunters, a tank length of at least 120 cm (4 feet) is highly recommended to allow them to reach full speed.

Sleeping Habits: Unlike the Red Coris, which buries in sand, the Blunthead Wrasse typically wedges itself into rock crevices or spins a mucus cocoon at night. A sand bed is not strictly necessary for their survival, but plenty of live rock is essential.

Tank Mates: They pair well with larger, boisterous fish such as Tangs, Angelfish, and larger Damsels. Avoid keeping them with very small, "thread-like" fish that might be mistaken for prey.

Care Level Moderate	Temperament Semi Aggressive	Diet	Reef Compatible Caution
Water Parameters	Maximum Size 15cm	Minimum Tank Size 300L	Origin It spans from the Red Sea and East Africa across to the Line and Tuamotu Islands, reaching as far north as southern Japan