How Smart Are Fish?   

Introduction:

Most fish are vulnerable to predation and have developed behavioral mechanisms to increase their chances of survival.  Depending on the natural environment and species, this can involve changing their skin color to resemble their background or just establishing a preference for a place where they are less visible.  This activity will involve testing small fish to determine whether they have a preference for the background color in their environment depending on prior adaptation.

National Standard Addressed:

The Unifying Concepts and Processes standard- Evidence, Models and Explanation is addressed in this lab because students are able to see direct evidence of the fish behavior when it chooses the light or dark side of the pan.

The Science as Inquiry standard- Understandings about Scientific Inquiry is covered because students will gain a better understanding of scientific inquiry when they run the experiment and learn how to ask questions that will help them complete their activity.

The Life Science standard- Regulation and Behavior can be observed when the fish are released to choose a side of the pan to swim into.  By observing their behavior we can better understand the way they live.

The Teaching standards- Promotion of Inquiry and Constructivism are both covered because students will be involved in inquiry based learning and constructing a productive working environment.

Objectives and Benchmarks:

The activity demonstrates the instinctive nature of the behavior of a small fish that is vulnerable to predation.  Students will be able to list the adaptations of fish to their environments.  They will also be able to list specific behaviors of the fish.

Materials:

Minnows or other small fish (Bait shop shiners are inexpensive and work well. Try to stay away from fat-head minnows. They take longer to change color.)     

Aeration Apparatus for Tanks   Fishnets

Black & White Plastic Wash Tubs for Acclimation            Choice Pans with Fish Traps    Corrals

Advance Preparation:

Spray-paint an aluminum pan so that one half is black and the other half is white.

Spray small loaf pans Black & White and cut vertical slits in one side to create a door to release the fish.

Obtain minnows and aeration apparatus for tanks.  Acclimate minnows to different colored tubs.

Procedure:

Have the students observe the minnows in the tanks and describe what they see.  Ask, What will happen if the fish are moved from one tank to another? 

There will be two tubs of minnows that have been acclimated to either a Black or White background overnight before the experiment.  The students will have a test pan that is painted half Black and half White.  Class groups will be set up in a series to pass fish along and repeat the test.  Each group will alternate the left/right color placements of the background.

Students should place a holding corral of the same background color in the very middle of their test pans right on the line where the color changes. They should then capture a fish from the same colored tub as the background and place it in the corral.  After the fish is calm in the pen they should allow the fish to swim out and record the color of the side it swims to first.  Place the fish in the next group.s pan and allow them to repeat the test.  After all of the fish have been tested, repeat the experiment, but use a corral that is the opposite color from the adapted environment.  For this test, time the placement in the corral so that the fish spends exactly 75 seconds on the changed environment before release.

Questions for students:

What are the variables that need to be controlled in this experiment?  Why do you think you might need to switch the left/right placement of the dark/light background in the test design?

If the fish swam to either side as a random choice, what would the ratio of dark/light or left/right selections be?

Students should plan how they will record the data for their group before the start of the trials.  When the group trial is finished, they will need to obtain the data from all of the groups for their written synopsis.

Things to Consider:

Compare your class results with the prediction you made as to what the fish choices would have been if they were just due to random choices. Did the fish adapt to the color of the background?  

Possible Integration:

One possible way to integrate this activity into another subject area is math.  Having the students do charting, graphs, and descriptive statistics of their findings will help to strengthen their math skills.

Critical Concepts:

Visit this link for a visual of the fish lab!