An Analysis of Fish Behavior: Water Temperature, Feeding Habits and Habitat Patterns

The behavior of fish refers to the patterns of feeding, breathing, movement, habitat and reproduction that fish have developed over long periods of natural evolution. Understanding these habits has practical reference value for aquaculture, angling, and home aquarium keeping alike.

Fish are ectothermic animals, meaning their body temperature changes with the water temperature, so water temperature has a major influence on their activity. Within a suitable temperature range, fish have a strong appetite and swim actively; when the water is too hot or too cold, they reduce their foraging and may even hide in deep water to escape the heat or cold. This is also why the depth at which fish are active and their level of activity change markedly with the seasons.

In terms of feeding habits, fish can be broadly divided into herbivores, carnivores and omnivores. Grass carp (Ctenopharyngodon idella) feed mainly on aquatic plants and tender vegetation; carnivorous fish such as the mandarin fish (Siniperca chuatsi) like to prey on small fish and shrimp; crucian carp (Carassius auratus) and common carp (Cyprinus carpio) are typical omnivores with a broad diet. Knowing the feeding habits of different fish is an important basis for formulating feed and choosing bait.

In terms of respiration, the vast majority of fish rely on their gills to obtain dissolved oxygen from the water. The level of dissolved oxygen in the water directly affects the survival state of fish; fish gasping at the surface on close, muggy days is often a sign of oxygen deficiency. As for habitat, different fish have their own preferences for water layers: some are usually active in the middle and upper layers, while others live on the bottom year-round. Most fish also have an innate tendency to school, to be attracted to light, or to hide near obstacles.

Familiarity with fish behavior helps farmers scientifically regulate water quality and arrange feeding reasonably, and it also helps anglers choose the right time and spot to fish. Overall, observing and working with the habits of fish is the foundation for raising fish well and catching fish well.