Water temperature modulates social behavior of ornamental cichlid (Pterophyllum scalare) in an artificial system

ABSTRACT Environmental changes can cause physiological alterations in fish, which may affect some behavioral patterns. We evaluated the effects of water temperature on the aggressive behavior of male freshwater angelfish, Pterophyllum scalare. We subjected pairs to three water temperature conditions: low (23.8 ± 0.8°C), medium (27.9 ± 1.2°C), and high (31.7 ± 1.0°C), with eight repetitions each. We assessed latency to fighting, aggressive interaction frequency, and territorial defense. In low and high temperatures there was a reduction in aggressive behavior exhibitions in comparison to medium temperatures (P < 0.05). As a result, water temperature can influence aggressive motivation and territorial establishment, given that temperatures closer to species optima (27.9 ± 1.2°C) can favor social contests for an Amazonian ornamental cichlid species, P. scalare.