Observing Behavior in Fish

Observing Behavior in Fish Animals of the same species often use aggressive behavior to signal others to retreat, but rarely do they hurt each other. In this investigation, you will examine some stimuli that provoke aggressive behavior.

Problem What triggers the aggressive behavior of male Betta fish? Materials •male Betta fish •colored pencils or markers •popsicle sticks •aquarium net •transparent tape •construction paper •clear plastic box w/ water •small mirror •watch with a second hand

Experiment Part A: Observing Aggressive Displays 1.Collect a male Betta fish for your experiment. CAUTION: Do not touch the fish with your hands. Fish are easily injured. 2.Observe the betta’s behavior in the aquarium. 3.Place a mirror against the side of the box so that the fish can see its reflection. Observe and record the betta’s behavior below. Remove the mirror within 1 minute so that the fish does not habituate to its reflection. Questions for Part A: a. What was the betta’s behavior when there was no additional stimulus? b. How did the betta’s behavior change when the mirror was added?

Part B: Identifying the Stimulus for Aggression 4.Formulating Hypotheses: What feature of a Betta provokes aggressive behavior in other Bettas? Is it color, size, movement, or something else? Record a hypothesis of what provokes aggressive displays by Bettas. Base your hypothesis on your observations of Bettas in Part A. Hypothesis:

5. Design an experiment that will use paper models of Bettas to test your hypothesis. You can tape the models to popsicle sticks and use colored pencils or markers to add details. You need to test at least 8 situations. Write the plan for your experiment. Have your teacher check your plan before you begin your experiment. Experimental Plan:

6.Carry out your experiment. Record your observations of the betta’s behavior in the data table below. CAUTION: To avoid exhausting the Betta, always allow it at least 1 minute of rest between stimuli. 7.Wash your hands with soap and warm water before leaving the lab.

Data Table: Betta reactions to characteristic tested Color Size Movement Other Betta Behavior

Analyze and Conclude 1.Controlling Variables: Identify and define the manipulated and responding variables in your experiment. 2.Observing: Did the male Betta exhibit aggressive behavior? If so, how did it show aggression? 3.Evaluating: What stimuli provoked the most aggression? Did your observations support your hypothesis? 4.Inferring: Male Bettas are more aggressive toward other males when a female Betta is present. How can such a behavior be an advantage to the male? How does it help the species survive? 5.SAFETY: Explain how you demonstrated safe practices when working with live fish in this investigation.