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What Many Pet Stores Will Not Tell You: The Real Reason So Many New Tanks Fail

The Secret is Cycling

Countless new aquarium hobbyists find themselves struggling with their first tank. Even if they are doing everything they are told, the fish just do not make it and their tank refuses to flourish. Many fail to understand the importance of cycling and how it is crucial in maintaining a healthy tank ecosystem. Without the bacteria used in cycling, all an aquarium would be is a box of water with an unhappy fish. Fish depend on a stable environment around them to survive, which makes it imperative that a tank replicate and become a true ecosystem. This process of developing this ecosystem in a tank is commonly known as cycling.

Ammonia is the main ingredient of the metabolic waste that fish produce. Ammonia may sound familiar, as it is a common ingredient in cleaning supplies such as glass cleaner. All this is to say that ammonia in a fish tank is a big red flag. However, it is necessary to start with a small amount in order to feed bacteria and allow a colony to develop. When a fish tank contains a hearty colony of bacteria, that usually indicated that the fish will also thrive.

Ammonia may be bad news in a tank, but it is necessary to start a healthy ecosystem that is capable of supporting life. Through a series of complex chemical reactions done by bacteria, ammonia will change form. It will first turn into nitrite, which is also toxic, and then finally nitrate, which is necessary for plant growth in the wild.

Once a nutrient source is added, whether that be bottled ammonia starter or simply regular fish pellets, the time comes to add the bacteria. Be aware, it takes time for a bacteria colony to truly flourish. They must consume the ammonia and reproduce, colonizing surfaces in the tank or filter such as the substrate, décor, or bio-media. There must be enough bacteria to have converted all of the ammonia and nitrite to nitrate, with ammonia and nitrite reading at zero on a water test, and the nitrate which should be reading generally under twenty parts per million at this stage.

Time to Add Fish

When all your tests meet the criteria, it is time to add the first fish.

  • It is important to note that adding too many fish at once can cause the production of a disproportionate amount of ammonia to the bacteria needed to process it. This could cause ammonia levels to spike and read very high which is very dangerous to fish. Adding only a few small fish is a wise decision, as the bacteria will reproduce with the population reflecting the amount of ammonia being excreted by the fish. They will multiple until they have reached a sort of carrying capacity in the tank, having enough numbers to efficiently process the ammonia being provided to them.
  • The population will always fluctuate in conjunction with the varying amounts of nutrients going into to the tank, though we want as much consistency as possible so small fluctuations with only adding a few fish at a time means it is less likely for an ammonia spike because the bacteria has less reproducing to do to match the ammonia levels.
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Use in accordance with the color matches in your preferred test kit.

Final Ammonia ReadingFinal Nitrite ReadingFinal Nitrate Reading

0 ppm

0 ppm

ideally <25 ppm

The Basic Steps

  • Dechlorinated/Conditioned Water
  • Nutrient source and Bacteria Starter
  • Confirmation through water tests

Nitrate Buildup

  • As time progresses more and more nitrate will build up in the tank.
  • In the wild many factors are involved in the reuptake and distribution of nitrates, which many times involved plants using nitrates to grow and form new tissues.
  • The bacteria may do most of the work for us, but considering the confined environment of a home aquarium, there still needs to be manual removal of the nitrates through water changes, which are recommended to be done around every other week, however this can vary as every tank is different.
  • Nitrate buildup can still be very deadly to fish, so doing regular water changes (about a third to a half of water removed from the bottom where waste has accumulated, as to not remove too much bacteria and upset the balance) are necessary for a healthy aquarium and healthy fish.
  • There are other helpful tools that contribute to the uptake of these nutrients such as a carbon or resin filter insert that absorbs nutrients, however those must be removed after a certain period.
  • Plants are also very helpful and create a unique experience in caring for the aquarium. Though they may require special lighting, they are a good investment to those who value a natural scape. Plants will even help with oxygenating the water and providing cover for more timid species.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

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