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 03421-6.6 July 2001

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

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

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

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.

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

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.

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

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

Dissolved Oxygen and Water Quality Process of photosynthesis effects amount of oxygen in water (20 - 30 times less in water than air) CO2 + Water ----> sugar + O2 + H20 As temperature increases, DO decreases Causes decrease in growth and reproduction

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