Survival of the Goldfish Lab!
Objective: Students will simulate natural selection with a population of edible goldfish and
understand how different environmental conditions may affect organisms.
Introduction: Goldfish are aquatic creatures that typically live in ponds or small lakes.
Their size ranges from 6-20 inches depending on their breed and species. Most goldfish
have been commercialized to live in aquariums or house ponds and thrive on a varied diet
which includes pellets or flakes made of vegetables, fruits, and some animals such as
shrimp, worms, or daphnia. In this lab we will be referring to six different colored species
of edible goldfish that each have different adaptations. Use the adaptations below to
decide which species is best adapted to the environment, Staffordshire Pond. Remember
that color can also be an adaptation if it allows the organism to camouflage with its
surroundings.
Problem: Which colored goldfish species is best adapted to live in its unpredictable
Staffordshire Pond environment?
Goldfish Adaptations:
*Carassius amarillo (yellow) – Medium size, feed near surface. Bright coloration to attract mates.
Survive under low oxygen conditions and prefer salty and warm water concentrations. Predators:
Big Mouth Bass. Diet: Insects and worms.
*Carassius verde (green) – Small in size, very quick. Find refuge in the thick grassy areas in the
shallow, warm waters. Can survive in low oxygen levels. Adapted to warmer waters. Predators:
Frogs. Diet: Worms.
*Carassius marron (brown pretzel) – Live near rocky areas. Camouflage with darker surroundings.
Large in size. Torpedo shape designed to swim well. Long, sticky tongue to catch prey. Survives
best in cooler areas with high oxygen concentrations. Predators: Snakes and Baby Alligators. Diet:
Snails.
*Carassius naranja (orange) – Mutualistic relationship with Red-Eared Slider Turtles. Feeds off
green algae and parasites on the turtle shell with its sucker-like mouth. Very small and attach to
the turtle shell for movement. Bright coloration to attract mates. Survives with low oxygen levels
in warmer water. Predators: Bluegill Fish. Diet: Green Algae and Parasites.
*Carassius morado (purple) – Slow swimmers, large and fat in size, better adapted to cooler, deeper
waters with high oxygen concentrations. Predators: Snapping Turtles. Diet: Fish Larvae
*Carassius negro (black chocolate) – Large in size. They are predators that sit and wait under the
cold, muddy bottoms for their prey to swim by. Prefer turbid waters and low oxygen
concentrations. Predators: Wading Birds. Diet: Freshwater Shrimp and Crayfish
Procedure
1. Use the information above to fill in the Goldfish Adaptation Chart below.
2. Fill in your hypothesis.
3. Obtain a mixed population of goldfish species from your teacher.
4. Place your fish on a paper towel and record the numbers of orange, purple,
brown, green, yellow and black fish species on the first data table. These fish
represent generation 1 (G1), the starting generation.
5. It is worm mating season and there are plenty of worms! All goldfish species
affected will now be quadrupled (4 times). All other fish populations double in
size for the following generation. Make adjustments in your fish populations
and record your results under generation 2 (G2).
6. A factory nearby releases chemicals that are deadly to ALL turtle species. All
affected goldfish populations will either triple or halve in number. All other
fish populations double in size for the following generation. Make adjustments
in your fish populations and record your results under generation 3 (G3).
7. There is a cold front that sweeps half (1/2) of any populations that do not
survive well in cold waters. All other fish populations double in size for the
following generation. Make adjustments in your fish populations and record your
results under generation 4 (G4).
8. There is a new exotic and aggressive species of Asian Fish that attacks ALL
BRIGHT COLORED goldfish. All affected species are now extinct. All other
fish populations double in size for the following generation. Make adjustments
in your fish populations and record your results under generation 5 (G5).
9. An invasive plant called the Giant Salvinia accidentally reached the pond.
Salvinia has grown over half of the pond’s surface and has decreased the oxygen
supply tremendously. All fish population that are affected will halve (1/2) in
population. All other fish populations double in size for the following generation.
Make adjustments in your fish populations and record your results under
generation 6 (G6).
10. Calculate the percentages for each color of goldfish and make a line graph for
the pond goldfish populations. (Part/Whole) x 100=%
Name:___________________________ Date:___________ Period:________
Goldfish Adaptation Chart: fill in the chart below with the information above.
Species
Habitat
Diet
Predators
Adaptations
Yellow
Green
Brown (pretzel)
Orange
Purple
Black
(chocolate)
Hypothesis: After reading the information above in the Introduction and Goldfish
Adaptations, predict which goldfish is best adapted to survive in the Staffordshire Pond.
Number of Goldfish Data Table:
Generation Orange
1
2
3
4
5
6
Brown(pretzel) Green
Yellow
Purple
Black(chocolate) Total
Yellow
Purple
Black(chocolate) Total
Percent% of Goldfish Data Table:
Generation Orange
1
2
3
4
5
6
Brown(pretzel) Green
Graph the Percent% of Goldfish over time. This will be a line graph with 6 data
lines. Be sure to include a title, label on the x axis and y axis, and a color key to
the side.
Conclusion:
1.
Which fish color was the most common in the First Generation? Which is the least
common?
2.
Which fish color is the most common in the Last generation? Which is the least
common?
3. What is the species name for the black chocolate goldfish?
4. Why do all the goldfish share the same genus name?
5. Did any fish go extinct? Why?
6. Which color(s) of fish species were best adapted and why?
7. How does this goldfish lab show natural selection?
8. Use an example from this lab to explain what “survival of the fittest” means and
how it is related to today’s goldfish lab.
9. Write a CER conclusion to explain if your hypothesis was supported or not.