What do Fish Want

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What do Fish Want??

• The importance of Water Quality
• and Testing Water

Original by Amy Gerhardt Modified by Georgia
Agricultural Education Curriculum July, 2002
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Topics of Importance

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

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Components of Water

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

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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

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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.

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• 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

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• 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.

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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 fishs bloodstream, unable to move
  nitrates and fish suffocates

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• 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

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Dissolved Oxygen and Water Quality

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

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