Middle School Lesson Plan: Population
Density in Fish and Limiting Factors
Affecting It
JAMAINE BARR
Charles Drew
Middle School
KENT LANDON
Thomas Jefferson
Middle School
SANDRA M. MOREJON
Cutler Ridge
Middle School
Subject: Comprehensive Science
Grade Level: 6-8
Topic: Population Density in Fish and How Limiting Factors Affect It
Length of Lesson: 5-6 weeks
Strands/Standards/Benchmarks:
Processes of Life
• Understands that the system within living things respond to changes in the environment
• Determines the behavioral responses of different organisms to common stimuli (For
example: light, temperature, pressure, moisture, etc.)
How Living Things Interact with Their Environment
• Knows that biological adaptations include changes in success in a particular
environment
• Understands the consequences that might result when changes occur in populations.
• Knows possible causes for a species to become threatened, endangered, or extinct.
• Knows the interrelationships in a local ecosystem.
The Nature of Science
• Uses systematic, scientific processes to solve problems and reach conclusions.
• Extends and refines knowledge of how to identify the independent and dependent
variables in an experiment.
• Knows the care, safe practices, and ethical treatment that are appropriate when using
animals in field and laboratory research.
• Extends and refines use of a computer to collect, analyze, and report scientific findings.
Introduction:
The teacher will give some background information to students about Goldfish. (See
attachment 1). The type of fish that will be used in the experiment will be the common
Goldfish (Carassius auratus) called Fantail Black Moor.
Background information:
The Goldfish hatches within 3-4 days. By the end of the first day the eggs are a color tan
to yellow and some are color white. The ones that are most fertile are clear. The other
ones are not fertile and will most likely get fungus. Once fungus appears it should be
removed immediately so that the fungus will not spread to other fish. There are some
breeders that will add methylene to help reduce the occurrence of fungus. The fish will
hatch from the back part, showing its tail first then using it will release its head. At birth,
the Goldfish is about 1/16th to 1/8th of an inch and has two black eyes, a long notochord
and a full yolk sac. If a fish falls to the bottom, there is no problem. After 48 hours a
fish starts to absorb their yolk sac and an air bladder and a fin will become noticeable.
After this time they will also start to fill their air bladders which will help the fish to start
swimming and seeking food. They will eat anything they can put in their mouths and that
is why it is important to have food in your hand.
The Goldfish will mature in about 1 year and are at their prime during their 3rd year. A
male will mature when his tubercles appear on the pectoral fins and gill covers. This
does not always occur, however, but can also be seen in females. Goldfish can live to be
over 10 years old.
The Goldfish need a diet high in carbohydrates which they can obtain by eating tetramis
flake food, dried shrimp, live mealworms or any variety of these foods in pellet form.
These fish should be fed once daily. They are not picky eaters.
There are some toxins to be aware of in the tank. Whether eaten or not, the processes can
make food into ammonia. In turn, it can become toxic and turn into equally toxic nitrate.
There are also other factors to watch out for.
Hypothesis:
In this experiment the student will be test the mortality rate of Goldfish due to limiting
factors.
Instructional Objectives:
Students will collect data over a period of 5-6 weeks for the experiment of Population
Density of Fish and How Limiting Factors Affect It.
Students will graph data results and write discussion on results.
Materials:
- 3 10-gallon tanks
- Set up materials for tanks. Example: Plants, background.
- Goldfish
- Fish food
- Thermometer
- pH tester
- Ammonia tester
- Fresh water for tanks
Methods:
Set Up of Experiment:
Data: Data will be shared by class and by schools. Data will be compared and results
will be presented using graphs and charts in different colors using Microsoft Excel.
Variables: The variable will be the amount of fish living within a set volume.
Constants: The constants in the experiment will be the food, the time the food is given,
light, temperature, volume of water, and initials pH levels.
Procedure:
1. Obtain 2 10-gallon fish tanks. Add a carbon filter to each tank.
2. Add 5 gallons of fresh water to the tanks.
3. Label tanks #1,#2, and #3.
4. To tank # 1, add 5 fish to it.
5. To tank #2 add 10 fish to it.
6. To tank # 3, add 15 fish to it.
7. Students (working in groups of 5) will monitor temperature using a thermometer.
Students will record this every 2 days.
8. Students are to give each tank the same amount of food each day and at the same
time during the day.
9. Students will monitor the pH to determine acidity or basicity. Students will keep
a record of the pH levels daily.
10.Use ammonia tester to check the levels of nitrates of ammonia and record results.
11.Check to make sure fish are surviving and record any fatalities over the 6 weeks
periods.
Group Name: ________________________
Tank # 1
Week 1
Measurements
Number of Fish
pH Level
Ammonia
Temperature
Week 2
Measurements
Number of Fish
pH Level
Ammonia
Temperature
Week 3
Measurements
Number of Fish
pH Level
Ammonia
Temperature
Week 4
Measurements
Number of Fish
pH Level
Ammonia
Temperature
Week 5
Measurements
Number of Fish
pH Level
Ammonia
Temperature
Week 6
Measurements
Number of Fish
pH Level
Ammonia
Temperature
Monday
Tuesday
Wed.
Thursday
Friday
Monday
Tuesday
Wed.
Thursday
Friday
Monday
Tuesday
Wed.
Thursday
Friday
Monday
Tuesday
Wed.
Thursday
Friday
Monday
Tuesday
Wed.
Thursday
Friday
Monday
Tuesday
Wed.
Thursday
Friday
For Tank # 2 and #3, there will be same tables as above.
Sample Charts made with Microsoft Excel:
Mortality Rate of Goldfish for Tank # 1
3
2.5
2
Week 1
1.5
Week 2
1
Week 3
0.5
0
Mon.
Tue s.
Wed.
Thur s.
Fri.
Days of the Week
Attachment 1
The Common Goldfish is a type of carp. These hardy fish have been kept in ponds
and aquariums for centuries in Asia. They have a life span of about 10 years. When
Goldfish return to the wild, they revert to their natural colors (green to black) in just a
few generations.
If kept in an aquarium, a 2-inch long Goldfish should have at least 2 gallons of water.
In general, at least one gallon for each inch of fish is necessary or the Goldfish will
become stunted and will have a shorter lifespan.
Anatomy: This brightly-colored fish has orange scales. The average Goldfish grows
to be about 3 to 5 inches (8 to 13 cm) long. The largest Goldfish are roughly 10 inches
(25 cm) long.
Diet: Like all carp, Goldfish eat tiny plants and animals found rooting in the mud on
the pond floor.
References:
http://www.enchantedlearning.com/subjects/fish/printouts/Goldfishprintout.shtml