Pistol Shrimp are very interesting and can **** well with Goby Fish. Pistol shrimp are usually blind, a pistol shrimp will dig a hole and then a pair of gobies will swim in to live with them, in return for digging the hole the pistol shrimp will be protected by the gobies and even get food. Usually the goby sits at the entrance to the cave and the pistol shrimp is busy clearing the passage, when the pistol shrimp comes out to dump the gravel it always puts one of its tentacles on the goby's body, and when the other fish attack, the pistol shrimp escapes back into the cave as soon as the goby moves.

The author uses these two creatures to illustrate the relationship between Yukiho and Ryoji **** born.