What does Japan regard as a symbol of love loyalty?

Sponges sometimes find a pair of live shrimps in the sponge. Here are several pairs of male and female shrimps. They got into the sponge and lived there. You can't get out when you grow up. They were trapped inside until they died of old age. Sponges provide them with nutrition, and shrimps clean the dirt in the pores of sponges, which is mutually beneficial and harmonious. This phenomenon is biologically called "sharing with the old". A pair of shrimps in a sponge grow old together because they live in this "cage" until death separates us and becomes a symbol of loyal love. Japanese people often give them to couples as wedding gifts, and shrimp is also euphemistically called "couple shrimp".