Here's why:
* Spawning Location: Most fish species release their eggs in specific locations within the tank, often on plants, rocks, or even in open water. This varies depending on the species.
* Parental Care: Some fish species are mouthbrooders, meaning they hold the eggs in their mouths until they hatch. Others might guard the eggs or fry (baby fish) in a specific area.
* Instinct to Avoid Predators: Fish instinctively try to avoid predators, and the bottom of the tank can be a vulnerable spot.
However, there are some exceptions:
* Livebearers: Livebearing fish, like guppies and mollies, give birth to live young. These fry are typically born in open water and might spend some time near the bottom initially, but not necessarily because they are giving birth.
* Bottom-Dwelling Species: Some fish species naturally live at the bottom of the tank and may spawn there as well.
Overall: The location of spawning and the behavior of the fish during the process depends heavily on the specific species. It's always a good idea to research the specific needs of your fish to ensure a safe and successful breeding process.