Behaviors

Relevant Behaviors in the Aquarium

Schooling Behavior (Shoaling vs. Schooling)

• Shoaling: Social grouping — fish prefer to stay together but do not move in a coordinated manner
• Schooling: Synchronized swimming — coordinated movement, a defense against predators
• Tetras, rasboras, and danios are schooling fish → at least 6 fish for natural behavior

Territoriality

• Cichlids: Many species mark their territory, especially during breeding season. Separate them physically or use decorations that block lines of sight.
• Bettas: Males are very aggressive toward each other and toward similar brightly colored fish
• Pufferfish (Tetraodontidae): They bite the fins of other fish

Hierarchy and Dominance

• Many fish have a dominance hierarchy
• The dominant individual may harass subordinates → sufficient space and hiding places are necessary
• In odd-numbered or larger groups, the harassment is spread out, and no single person bears the full brunt of the stress

Jump out of the aquarium

• Many species jump (especially: killifish, archerfish, hatchetfish, danios)
• Always use a lid on aquariums containing these species

Chemical Communication

• Fish release pheromones and alarm substances (Schreckstoff)
• When a fish is attacked, it releases substances that warn the school of danger
• The sense of smell is essential for Corydoras to find food

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The Aquarium Ecosystem