What is the difference between ceviche and tiradito?

Tiradito, the younger brother of ceviche, has only become well-known in the last 20 years or so. Its origins can be found in the approach of Japanese immigrants to eating raw fish, though some suggest it's closer to Italian carpaccio, popularised earlier in the 20th century by Genovese immigrants.

Two are the main differences between them: the cut and onions. While ceviche is cut in bite-size cubes and comprises a generous amount of onions, tiradito is sliced in fine, long pieces and carries no onions.

http://www.foodrepublic.com/2014/09/17/like-ceviche-sashimi-awesome-meet-tiradito/