Aquatics - The Nitrate Cycle

What is the nitrate cycle?

A natural process to manage water quality and chemistry

What is water chemistry?

Describes the combined salinity, hardness and pH of the water

What is water quality?

Describes the amount of pollutants in the water

Why does water quality in aquariums start to deteriorate once fish have been introduced?

• Fish waste is produced (ammonia)

• Plants die/shed leaves which decompose and produce ammonia

• Uneaten food breaks down into ammonia and food excreted as ammonia

1st Stage of Nitrate Cycle

Ammonia produced is converted by Nitrosomonas (bacteria) into slightly less harmful nitrite

2nd Stage of Nitrate Cycle

Nitrites are converted by Nitrospira into least harmful nitrate

How to manage high levels of Nitrate?

Water changes and maintenance. Only toxic at high levels

How is ammonia produced?

Excretion from fish and degrading biotic matter.

What levels of ammonia should you aim for in an aquarium?

0 levels

What can high levels of ammonia cause?

Ammonia burns and death

Is Nitrite toxic?

Less toxic than Ammonia but still toxic in high levels

What is Nitrite broken down by and what does it produce?

Broken down by Nitrospira into a less toxic Nitrate

What levels in ppm of nitrite should there be in tanks?

Less than 0.3ppm

What can high levels of Nitrite cause?

Can cause stress and increase the risk of disease

How can Nitrate be reduced?

By partial water changes and adding live plants

What levels in ppm of Nitrate should you aim for?

Less than 25ppm

What does pH measure?

Acidity/alkalinity

Why is the right levels of pH important?

Fish are adapted to a certain pH based on the species and some fish can’t survive if the pH is too different

Why is having too many fish bad for balance?

More fish = more waste which means ammonia increases

Why is too much food bad for balance?

Too much food = leftover food which rots and converts into ammonia

Why is too little food bad for balance?

Too little food = Not enough ammonia which means that the bacteria will starve

Side effects of poor balance

Low oxygen levels, fluctuations in pH, algae blooms

Where do fish store fat?

Around internal organs

Why is an excessive build up of fat bad?

Can lead to organ failure

What are the 3 common organs affected by overfeeding?

Liver, heart, kidneys

What can underfeeding cause?

Incorrect nutrition which leads to health problems

What can underfeeding result in?

Immunosuppression which means that they are more susceptible to diseases and pathogens

What else can underfeeding affect?

Poor organ development and growth and vitamin and mineral deficiencies