1. External changes: Male guppies exhibit significant changes in behavior and appearance before mating and spawning. Their body colors may become more vivid, especially their dorsal and caudal fins, to attract females. Male guppies may also become more active and aggressive, and they may chase and show themselves in the aquarium.

2. Oviposition behavior: When guppies are about to lay eggs, they will start looking for suitable spawning places. Female guppies usually choose suitable places to lay eggs, such as the bottom of plant leaves, crevices in rocks or other hidden corners. They will clean the spawning area and swing their tails to attract males.

3. Male egg protection behavior: Once the female guppy lays eggs, the male will assume the responsibility of protecting the eggs and young fish. They swim around the eggs and remain vigilant to prevent other fish from approaching. Male guppies maintain direct contact with eggs and ensure good ventilation and water flow of eggs.