The Blue Tarosu are the more common of the two variations of Tarosu. They are first encountered shortly after Link enters the Dark World. They roam around in the Overworld, first encountered just southeast of the Pyramid of Power. In many ways they behave very similar to that of their Light World counterparts, the Sword Soldiers. They will patrol back and forth, but if Link comes anywhere near them, they will charge directly at him.
Blue Tarosu are some of the weakest enemies that Link encounters within the Dark World. While many of the overworld enemies that Link counters do multiple hearts of damage, the Blue Tarosu will do just a 1/2 heart of damage if it comes into contact with Link. They don't have much health either, as Link can defeat them with two swipes from his Master Sword.
The Red Tarosu are a rare enemy that appear in the Dark World. A single Red Tarosu appears appears just north of the Village of Outcasts but they are more abundantly found within Ganon's Tower. Instead of the Rods that they Blue Tarosu wield, the Red Tarosu carries a much more dangerous trident spear.
The Red Tarosu are much more observant of their surroundings in comparison to the Blue variety. The Red Tarosu can sense Link from a much greater distance and will immediately start charging at him. These Red Tarosu are more persistent and move significantly faster than the Blue Tarosus.
In addition to their improved awareness and speed, Red Tarosu also deal more damage, delivering a full heart of damage each time they come into contact with Link. They are also more resilient, needing three strikes from Link's Master Sword to be defeated.