90 min · module 02 of 06
The Nitrogen Cycle: Invisible Hustlers
Bacteria do the dirtiest, most important work.
Watch & Learn
The Nitrogen Cycle
Learning Objectives
- 01.Trace ammonia → nitrite → nitrate.
- 02.Name the two bacteria families that make aquaponics possible.
- 03.Explain why a brand-new tank can't grow plants right away.
Hands-On Activities
- Build a paper-cup model of the nitrogen cycle.
- Use a test strip on real tank water and read results.
- Group debate: 'Which player matters most — fish, bacteria, or plants?'
Materials
Water test stripsCupsIndex cards
Vocabulary
Ammonia (NH₃)
Toxic waste fish release through gills and pee.
Nitrite (NO₂⁻)
First conversion step — still toxic, but lower.
Nitrate (NO₃⁻)
The plant fertilizer end of the cycle.
Cycling
The 4–6 week process of building bacteria before adding fish.
Discussion Prompts
- Why do we say bacteria are the real MVPs of aquaponics?
- What happens to fish if the bacteria aren't ready yet?
Check For Understanding
Q1. In what order does the nitrogen cycle move?
Q2. Which substance is the plant fertilizer?
Q3. Why can't you add a bunch of fish to a brand-new tank?