Tatsugiri are nominally edible, in the sense that the bodies of these pokemon are made of the same materials as other fish and dragons, and there is nothing about them which could not be broken down by your average piscivore's digestive system. Getting a Tatsugiri in there, however, is a far more difficult matter, as one generally has to go through the mouth first – and it is through the mouth that Tatsugiri take control of their would-be predators' brains.

Tatsugiri typically use this parasitic behavior to feed their partner, Dondozo, luring the affected pokemon into its mouth, and feeding on the scraps it leaves behind after it eats. Tatsugiri who are transported by wind or human action outside their natural habitat are known to form similar partnerships with other large aquatic pokemon, such as Clodsire in nearby swamps or Wailord in the Atlantic Ocean. However, as the Dondozo alternatives are simply puzzled, not evolved for partnership, they do not replicate the combination attacks which make Tatsugiri so menacing in Casseroya Lake or the Paldean League.

Rumors abound of Tatsugiri controlling humans, who presumably had mistaken them for sushi. People holding Tatsugiri in their mouths do not become food (as Dondozo has developed a healthy fear of Man, and refuses to eat them when offered) but are said to advance the interests of these pokemon in human society. Some of the acts attributed to Tatsugiri-controlled politicians, such as environmental legislation around their home lake, can only be considered benign. If these tales are to be believed, then nearly every deed the Paldean government does, for better or worse, is supposedly part of a sinister scheme to advance the interests of their Tatsugiri overlords; the Dragon Titan seeks world domination, and will do anything to obtain it!