Fish in a Jug Activity
By: Laura Canton
A. Standards Addressed:
B-6: The student will demonstrate an understanding of the interrelationships
among organisms and the biotic and abiotic components of their environments.
B. Performance Objectives
Upon completion of this activity students will:
 Identify different parts of the biogeochemical cycle
 Identify important components of an ecosystem
 Write a report on their observations and conclusions on their closed ecosystem
C. Lesson Plan
1. Concept Exploration
Students brainstorm the important parts of an ecosystem and how these parts may
be linked. Tell students that they will be given materials to construct a closed ecosystem
(fish in a jar). Their materials will include sand/gravel, plants, water, and guppies. Have
them team up and decide what kind of water (distilled or tap), how much water, how
much gravel, and how many plants. Students can also bring in decorations, such as
shells, for inside their jar.
2. Concept Introduction
This lesson explores interdependence within the aquatic biome. In this activity,
students learn that plants and animals in aquarium are interdependent, and need each
other for their continued survival.
Plants are dependent on animals to provide nutrients (through waste products and
decomposition) and, to some extent, the carbon dioxide they need for photosynthesis.
Animals need plants to supply some or all of their respiration and metabolism. In tact,
most of the oxygen used by the world's animals is actually produced by plants that live in
the oceans. Introduce these concepts to students through the Biogeochemical Cycle
powerpoint.
3. Concept Application
After the powerpoint lesson have students make adjustments to their plans based
on what they’ve learned about the biogeochemical cycle. Give each group a large plastic
jar and allow them to fill the jars with the proportions of materials they deem appropriate.
Let the jars sit for a day before adding plants. Let the jars sit for another day before
adding guppies. Explain the importance of slowly acclimating the fish to the new
environment, rather than just throwing them in the jar. Make sure each group gets at least
one male and one female guppy so that they can potentially have babies. Have each
group keep a journal and document changes in their jar each day (excluding weekends).
Observe jars for 28 days. NOTE: Once students place the lid on the jar, they may not
open it for any reason, not even to remove dead fish!
D. Evaluation
Students will write a report on their observations and conclusions from their
journal. It is important that students understand that they need to rationalize all of their
choices for their jar including:
 The type of water
 The amount of gravel
 The level of water
 The number of plants
 The place in the room the jar was placed
They must also discuss what happened to the fish and plants over the course of the
project, and their conclusions (as it relates to the biogeochemical cycle) as to why
what happened, happened!