Clear water doesn’t always mean healthy water. In this illustrated aquaculture mystery, students investigate stressed tilapia, separate observations from inferences, interpret fictional water-quality data and recommend practical actions.

Now includes an editable 10-slide PowerPoint for whole-class introduction.

Explore the series:
FREE challenge: /teaching-resource/-13639412
Case No. 001: /teaching-resource/-13639322

Students learn why total ammonia nitrogen (TAN), ammonium (NH₄⁺), toxic un-ionised ammonia (NH₃) and pH matter. Conclusions describe suspected stress, not a diagnosis.

Included

• 5 printable A4 student pages, teacher guide and 2-page mark scheme
• Editable PowerPoint: 9 student-facing slides plus 1 hidden teacher extension slide, 16:9. It introduces the mystery and TAN/NH₃ clue, guides the activity and includes teacher notes. Completed answers and data values are not shown.

Students practise fish-health observation, data interpretation, scientific reasoning and practical aquaculture decision-making.

Teaching time: 30–45 minutes, or two shorter sessions. No laboratory equipment required. All data are fictional.

Suitable for KS3 and KS4 Biology, environmental science and introductory aquaculture or land-based courses.

Designed by an aquaculture instructor. A little science, a little detective work and one curious black cat! (=^ェ^=)Clear water doesn’t always mean healthy water. In this illustrated aquaculture mystery, students investigate stressed tilapia, separate observations from inferences, interpret fictional water-quality data and recommend practical actions.

Now includes an editable 10-slide PowerPoint for whole-class introduction.

Explore the series: FREE Can You Spot the Sick Fish? and Case No. 001: Dissolved Oxygen and Fish Health Mystery.

Students learn why total ammonia nitrogen (TAN), ammonium (NH₄⁺), toxic un-ionised ammonia (NH₃) and pH matter. Conclusions describe suspected stress, not a diagnosis.

Included

• 5 printable A4 student pages, teacher guide and 2-page mark scheme
• Editable PowerPoint: 9 student-facing slides plus 1 hidden teacher extension slide, 16:9. It introduces the mystery and TAN/NH₃ clue, guides the activity and includes teacher notes. Completed answers and data values are not shown.

Students practise fish-health observation, data interpretation, scientific reasoning and practical aquaculture decision-making.

Teaching time: 30–45 minutes, or two shorter sessions. No laboratory equipment required. All data are fictional.

Suitable for KS3 and KS4 Biology, environmental science and introductory aquaculture or land-based courses.