Does a fishes brain tell it to stop eating?

Fish do not have a brain region analogous to the mammalian hypothalamus that controls feelings of hunger and satiety. This means that fish do not feel "full" in the same way that we do. Instead, they rely on a variety of internal and external cues to regulate their food intake.

Some of these cues include:

* Gut distension: As a fish eats, its stomach stretches. This stretching triggers nerve signals that travel to the brain, signaling that the fish is full.

* Hormones: Fish produce a variety of hormones that regulate appetite, including insulin, leptin, and ghrelin. These hormones work in concert to control the amount of food a fish eats.

* Environmental cues: Fish also use environmental cues to regulate their food intake. For example, they may stop eating when the light levels change or when the temperature drops.

* Social interactions: Fish may also adjust their food intake based on the behavior of other fish. For example, they may eat more when they see other fish eating or they may eat less when they are competing with other fish for food.

In general, fish eat until they are full. However, they may also stop eating if they feel stressed, sick, or if their environment is not ideal.