The Aquarium Depot
Ammonia (NH3)
Ammonium (NH4+)
Ammonia is the first toxic chemical that many fish keepers have dealt with and lost
fish to. The bane of a new tank setup and the eventual byproduct of over stocking and
ignoring the water quality of aquarium.
Ammonia is initially released from decaying organic material (dead fish, excess
food, fish waste, etc.) as the chemical ammonium (NH4+). Although ammonium is toxic
to a fish, it is nowhere nearly as deadly to fish as ammonia (NH3). Ammonium changes
to ammonia in the presence of an alkaline pH. Alkaline pH in water represent a surplus
of hydroxyl ions (OH-) which steal a hydrogen ion from the ammonium (NH4+) which
turns it into ammonia (NH3).
NH4+ + OH- = NH3 + H2O
When hydroxyl ions steal this positively charged hydrogen ion from ammonium, the real
killer ammonia is born and the pH of your water gradually lowers. Even a small amount of
ammonia can be fatal to some species of fish. Ammonia poisons a fish by causing the
hemoglobin in the red blood cell (the part of it that allows it to carry oxygen in the blood)
to turn into methahemoglobin. Essentially this makes the blood unable to carry oxygen in
the way that its supposed to. Most fish that suffer from ammonia poisoning will first show
lethargy, not swimming or acting normally, sometimes pumping their gills at the top of the
aquarium in an attempt to push oxygen rich water over the gills.
Thankfully ammonia is broken down by a bacteria found in almost every aquarium.
The bacteria is called nitrosococcus. This bacteria takes ammonia and water, oxidizing
it and changing it into nitrites (NO2-). As nitrites are created by this bacteria, positively
charged hydrogen ions (H+) are released into the tank, lowering the pH even further.
Nitrites, just like ammonia are very toxic to a fish and should not be ignored.
As a final byproduct of ammonia, the nitrites are converted again into nitrates.
Nitrates are still toxic, but to much less of a degree than ammonia or nitrites. Nitrates are
primarily used by plants and algae as a basic fertilizer.
Ammonium (NH4+)
Ammonia is the first toxic chemical that many fish keepers have dealt with and lost
fish to. The bane of a new tank setup and the eventual byproduct of over stocking and
ignoring the water quality of aquarium.
Ammonia is initially released from decaying organic material (dead fish, excess
food, fish waste, etc.) as the chemical ammonium (NH4+). Although ammonium is toxic
to a fish, it is nowhere nearly as deadly to fish as ammonia (NH3). Ammonium changes
to ammonia in the presence of an alkaline pH. Alkaline pH in water represent a surplus
of hydroxyl ions (OH-) which steal a hydrogen ion from the ammonium (NH4+) which
turns it into ammonia (NH3).
NH4+ + OH- = NH3 + H2O
When hydroxyl ions steal this positively charged hydrogen ion from ammonium, the real
killer ammonia is born and the pH of your water gradually lowers. Even a small amount of
ammonia can be fatal to some species of fish. Ammonia poisons a fish by causing the
hemoglobin in the red blood cell (the part of it that allows it to carry oxygen in the blood)
to turn into methahemoglobin. Essentially this makes the blood unable to carry oxygen in
the way that its supposed to. Most fish that suffer from ammonia poisoning will first show
lethargy, not swimming or acting normally, sometimes pumping their gills at the top of the
aquarium in an attempt to push oxygen rich water over the gills.
Thankfully ammonia is broken down by a bacteria found in almost every aquarium.
The bacteria is called nitrosococcus. This bacteria takes ammonia and water, oxidizing
it and changing it into nitrites (NO2-). As nitrites are created by this bacteria, positively
charged hydrogen ions (H+) are released into the tank, lowering the pH even further.
Nitrites, just like ammonia are very toxic to a fish and should not be ignored.
As a final byproduct of ammonia, the nitrites are converted again into nitrates.
Nitrates are still toxic, but to much less of a degree than ammonia or nitrites. Nitrates are
primarily used by plants and algae as a basic fertilizer.
pH
pH is one of the most widely tested parameters for water in a home aquarium. But
what are you testing for when you test your pH?
pH is the acidity or alkalinity of a liquid. For water, it is a measure of positively
charged hydrogen ions (H+) versus hydroxyl ions (OH-). When in even amounts, you
have a neutral pH of 7.0. In acidic water, pH below 7.0, you have a surplus of hydrogen
ions. The more of these hydrogen ions you have, the more acidic your water. In alkaline
or basic water, pH above 7.0, you have a surplus of hydroxyl ions.
Proper pH for a tank depends on the type of fish that you want to have. For a marine
tank (saltwater), the pH should be around 8.2. Freshwater fish have a variety of pH
ranges depending on the place of origin.
Amazon, South America: low - neutral 6.5-7.2
South East Asia: low - neutral 6.5-7.2
Livebearers: neutral - alkaline 7.2-7.6
Brackish: high 7.6-7.8
African Cichlids: high 7.8-8.2
Most fish that you purchase at a fish store are kept on county tap water. Ask what the
general pH is and your aquarium should be close to that for simplicity. Trying to alter the
pH of a community tank from your tap water’s average pH of 7.2-7.4 to a neutral 7.0 is
more work than necessary and is usually more stressful on the fish than it is beneficial.
Be sure to research the fish that you have or are thinking of buying to make sure they
can handle any specific pH requirements that they may have.
pH is one of the most widely tested parameters for water in a home aquarium. But
what are you testing for when you test your pH?
pH is the acidity or alkalinity of a liquid. For water, it is a measure of positively
charged hydrogen ions (H+) versus hydroxyl ions (OH-). When in even amounts, you
have a neutral pH of 7.0. In acidic water, pH below 7.0, you have a surplus of hydrogen
ions. The more of these hydrogen ions you have, the more acidic your water. In alkaline
or basic water, pH above 7.0, you have a surplus of hydroxyl ions.
Proper pH for a tank depends on the type of fish that you want to have. For a marine
tank (saltwater), the pH should be around 8.2. Freshwater fish have a variety of pH
ranges depending on the place of origin.
Amazon, South America: low - neutral 6.5-7.2
South East Asia: low - neutral 6.5-7.2
Livebearers: neutral - alkaline 7.2-7.6
Brackish: high 7.6-7.8
African Cichlids: high 7.8-8.2
Most fish that you purchase at a fish store are kept on county tap water. Ask what the
general pH is and your aquarium should be close to that for simplicity. Trying to alter the
pH of a community tank from your tap water’s average pH of 7.2-7.4 to a neutral 7.0 is
more work than necessary and is usually more stressful on the fish than it is beneficial.
Be sure to research the fish that you have or are thinking of buying to make sure they
can handle any specific pH requirements that they may have.
Water Chemistry
