I'm not saying that it's completely normal, but that does not mean that it is not uncommon. I don't think that the reason your gerbil's tail fell off was because of the jagged area, but because your sister pulled him by the tail. You should NEVER do this. If you do, the tail will either deglove or just break off.
Fish Spawning. Female fish lay eggs, with the eggs being fertilized by the males in close attendance. Eggs develop more rapidly (in a few weeks) in warmer temperatures, and more slowly in colder water (up to months).Most freshwater fish spawn in the spring, although salmon, char, and some trout spawn in the fall.ish Spawning. Female fish lay eggs, with the eggs being fertilized by the males in close attendance. Eggs develop more rapidly (in a few weeks) in warmer temperatures, and more slowly in colder water (up to months).
The release of fish eggs and their subsequent fertilization is called spawning. Most marine fish reproduce by releasing thousands of small eggs into the water for external fertilization. Egg-laying fish have a variety of methods for releasing the eggs. Some fish scatter eggs, which are fertilized by the male fish as they fall. Other fish attach the eggs to a surface, where they are then fertilized as they are released. Some fish release eggs into a nest of bubbles blown by the male fish.