1. The importance of Water Quality and Testing Water
What do Fish Want??
The importance of Water Quality
and Testing Water
From foukeffa.org
Written by Amy Gerhardt
GA Ag Ed Curriculum Office
To accompany the Georgia Agriculture Education Curriculum Lesson
July 2001

2. Topics of Importance Components of Water What do fish really want??
Ammonia
Nitrites
Nitrates
Dissolved Oxygen

3. Components of Water Key nutrient ions Phosphates, nitrates
Dissolved Gases
Oxygen, Carbon dioxide
Trace ions
Copper, iron, zinc, etc.

4. What do Fish Want?? Low ammonia and nitrate levels
Chemically clean water
Correct water pH and temperature
Low levels of organic pollution
Stable conditions in water

5. Ammonia and Water Quality
Ammonia is extremely toxic and even relatively low levels pose a threat to fish health.
Fish continually excrete ammonia directly into the surrounding water via special cells in the gills.
In a natural environment, such as seas, lakes and rivers, it would be immediately diluted to harmless levels.

6. However, in ponds, levels can rapidly rise to dangerous levels unless it is constantly removed, usually by biological filtration.
Additional amounts are produced from decomposing fish food and fish waste
Irritates gills, restricting the water flow over the gill filaments, respiratory problems and stress

7. Rub against solid objects, without water testing it would be very easy to wrongly conclude the fish had a parasite problem.
The fish response to toxic levels-loss of appetite, laying on the pond bottom with clamped fins, or gasping at the water surface if the gills have been affected.

8. Nitrites and Water Quality
Nitrite (NO2-) is formed when bacteria oxidizes ammonia produced by fish and decomposing organic matter.
Prolonged exposure to low levels can lead to stress, ulcers and fin rot
The main danger: transported across the gills and into the fish’s bloodstream, unable to move nitrates and fish suffocates

9. At low levels the fish may rub against solid objects or ‘flash’, gills will be pale tan to dark brown in color, gasping at the water surface.
Nitrogen cycle changes nitrites into nitrates, 2000 times less toxic to trout

10. Dissolved Oxygen and Water Quality
Process of photosynthesis effects amount of oxygen in water ( times less in water than air)
CO2 + Water ----> sugar + O2 + H20
As temperature increases, DO decreases
Causes decrease in growth and reproduction

11. Solutions to low level:
Stop feeding to increase organic material
Change partial water
Decrease temperature slowly