Aquatics - effect of stress and stocking density

What can cause stress?

• Temperature

• Illness

• Grouping

• Lack of/too much food

• Overcrowding

What is the definition of stress?

A physiological response to an internal or external stimuli that is outside of the ‘normal’ range

Why is stress the biggest contributor to aquatic diseases?

Because it lowers the immune system which causes immunosuppression

Signs of stress

• Behaviour

• Body condition score

• Growth and nutrition 

• Injury

• Fertility

• Disease

What does stocking density include?

How many fish can fit into the tank

What is stocking density?

A calculation that determines the number of fish based on the volume of water

Minimum requirement for a fish tank

1cm of fish per 1 litre of water

Formula to determine the total volume of a tank in litres

L * W * H (cm) / 1000 = L

What to do after calculating formula?

Remove 15% for substrate and enrichment

Other considerations for stocking density

• Feed quantity and quality

• Maintenance schedules

• Fish behaviours and temperament

• Plants

• Aeration