Buddhists don't kill animals because of their love, so they avoid the fishy smell. Moreover, for self-discipline, Buddhist children don't eat stimulating foods such as onions, garlic and leeks, so a real vegetarian meal is different from what people say today.
As early as when Sakyamuni Buddha preached in India, it was not forbidden to eat meat, but to drink, eat onions and eat garlic. Later, Buddhism was improved many times, and the Mahayana Buddhist precepts that China generally believed in were much more than those of primitive Buddhism, and there was a clear prohibition on eating meat. Monks pay attention to compassion and kindness, and eating meat is a way of killing life, which naturally has a great influence on practice.
For an egg, it depends on whether it is a fertilized egg. A fertilized egg can hatch chickens, so it is alive, so it is fishy. The unfertilized eggs can't hatch chickens, and eating them is not killing, so they are vegetarian. But people who don't eat any part of animals, including eggs and milk.
As we all know, Buddhism requires Buddhists to fast. The so-called vegetarian, the average person's understanding is vegetarian, that is, do not eat meat, that is, do not eat meat. In fact, the so-called obscenity in Buddhism is different from the understanding of ordinary people such as you and me. The so-called "meat" in Buddhism refers to vegetables with foul smell, such as garlic, green onions and leeks. The Shurangama Sutra says: raw meat makes you angry, and cooked food helps you to be immoral. So Buddhism requires fasting. The so-called "fishy smell" in Buddhism refers to meat, that is, the meat of various animals, even eggs. It is said that there is a saying in religious precepts that "five meats" and "three evils" are forbidden.