How Do Fish Lay Eggs?

There are three distinct types of fish eggs:

- Demersal eggs

- Pelagic eggs

- Adherent eggs

1. Demersal Eggs

Demersal eggs are heavy, sticky, and will usually sink to the bottom floor of the environment surrounding the fish. For instance, they may land on rocks, sand or even seaweed for some species. In other words, they rest on any kind of substrate (e.g. ocean floor). Their density means that they’re highly vulnerable to predators, so many fish species that lay these types of eggs will lay several thousand at a time (often in nests that provide some level of protection).

2. Pelagic Eggs

As their name suggests, these eggs are found higher up in the water column, drifting along at the whims of the currents. They don’t have sticky coatings and they’re less dense than Demersal eggs. This means that when they’re released into the water they float. Fish that lay pelagic eggs often spread them over larger distances than those that lay Demersal eggs.

3. Adherent Eggs

Adherent eggs are also referred to as “adhesive” eggs. This is because they use various methods of sticking to any number of surfaces, from gravel and rocks to underwater vegetation. As you might imagine, many adherent eggs are flat, which increases the surface area available for sticking to surfaces.