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Activity: Observing Fish Scales
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
NGSS Disciplinary Core Ideas


  • Forceps
  • Microscope slide
  • Dissecting microscope or hand lens


  1. Examine fish scales.
    1. Grasp a fish scale gently with some forceps and remove it from the body of the fish or from the specimen container.
    2. Place the fish scale on a microscope slide and examine it under a dissecting microscope. Look for rings, spikes, and other structures.
  2. Draw the fish scale and describe it.
    1. Make a note of the shape, thickness, and size of your fish scale.
    2. Identify the type of scale it is using Fig. 4.42. Explain your identification.
  3. Compare your scale specimens to other scales from the same fish.
    1. Repeat procedures 1 and 2 with scales from different parts of the fish (like near the head or tail).
    2. How does the size and thickness of the scales vary across the body of the fish?
    3. What other similarities or differences do you notice between the scales on different parts of the fish body?
  4. (Optional) Repeat procedures 1–3 with a different fish.
    1. Compare the scales from different parts of the body from the second fish
    2. Compare the scales from both fish to each other
      1. Which fish has bigger scales?
      2. Which fish has thicker scales?
      3. What other similarities or differences do you notice?


Activity Questions
  1. What can the type of scale on a fish tell you about the evolutionary relationship of your fish?
  2. How might scales on a fish be used in protection?
  3. Why do you think some fish have large scales and others have small scales?
  4. Why do you think some fish have no scales at all?
  5. If a fish scale makes rings as it grows, how might the rings be used to estimate the age of the fish?
  6. How do you think the type of scales on a fish might affect your ability to make a fish print?
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.