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).
Most spawning activity occurs at water temperatures around 10 C (50 F). Spawning can take place in streams or along shorelines. Rainbow smelt are found in streams and rivers only during their spawning migration. Females sized 185 to 224 mm (7.3 8.8 in) in length can release from 21,000 41,000 eggs each (Becker 1983).