Closer Urchin seen in this photo is a red tuxedo and the further is a regular royal tuxedo
 
 
The Royal Urchin, also known as the Tuxedo Urchin, is a popular species of sea urchin commonly kept in saltwater aquariums. As the name suggests, they have a striking black and white appearance, with a black body and white spines.
 
Royal Urchins are generally hardy and can tolerate a range of water conditions, but they do require a stable and well-maintained environment to thrive. They prefer rocky or reef-like environments with plenty of crevices and hiding places, and can often be found wedged between rocks or in small caves.
 
In terms of diet, Royal Urchins are primarily herbivorous and will graze on a variety of types of algae, including hair algae, macroalgae, and diatoms. They may also feed on other types of organic matter in the aquarium, such as uneaten food or detritus.
 
While Royal Urchins are generally peaceful and can be kept with a variety of other fish and invertebrates, they may damage delicate corals or other sessile invertebrates if they come into contact with them. Additionally, their sharp spines can cause injury if handled improperly, so care should be taken when handling them.