How can a fish tank nitrification system be established so that it is complete and stable? Hangtai Aquarium answers

Everyone excitedly gets a newly bought fish tank fully equipped, adds water, turns on the motor, and then asks, what is the next step? "Buy fish" - this is believed to be the answer that flashes into the brain fastest. However, after a week, the fish died one by one, and only then did they feel something was wrong. What was done incorrectly... The answer is often that the nitrification system was not fully established. The nitrification system means cultivating nitrifying bacteria to remove the toxins excreted by the fish. And if you also followed the normal process to age the water, why has the nitrification system still not been established well?

The outline of the whole system is: fish waste (ammonia) -> nitrite -> nitrate (the following data is for reference only, because too many factors make every fish tank somewhat different)

1. Initial stage

The fish are put into the tank, begin to discharge waste, and ammonia begins to accumulate. Ammonia is extremely harmful to fish. Usually, three days after adding fish, the ammonia concentration begins to rise.

Recommendation: 0.25-1.0 ppm: 25% water change. Halve feeding. 1.0-2.0 ppm: 50% water change, reduce feeding. >2.0 ppm: 60% continue water changes until the 2.0 ppm practice is followed.

2. Middle stage

Nitrosomonas bacteria begin to break down ammonia and convert it into nitrite. However, this is also harmful to fish. Some fish cannot tolerate nitrite = 1ppm. Nitrite concentration usually begins to rise after one week.

Recommendation: 0.1-0.5ppm: 25% water change, halve feeding. 0.5-1.0 ppm: 50% water change, reduce feeding. >1.0 ppm: continue 50% water changes until the 1.0 ppm practice is followed.

3. Later stage

After another week, nitrifying bacteria begin to grow. They grow relatively slowly, taking about 15 hours to double. Nitrifying bacteria break down nitrite into nitrate. A small amount of nitrate is acceptable to fish, and aquatic plants can also absorb it. However, if the concentration is too high, fish are also prone to dying. Regular water changes are needed to dilute the nitrate concentration. It is also best that the nitrate concentration does not exceed 20ppm.

Recommendation: keep at

There is only one secret to establishing the system: time

Because the needed nitrifying bacteria already exist around you and me. All everyone needs to give is a little time, and a little help.

On the first day, buy two or three relatively hardy fish, feed a small amount of food, and starting from the second day begin measuring the ammonia concentration. The concentration will continue to rise for several days. Do not be afraid.

After about a week, because of the growth of Nitrosomonas bacteria, it begins to enter the middle stage, and the ammonia concentration will decline quickly. During this period, if the fish really are not doing well, a small water change can be done to dilute the water in the tank. Correspondingly, the nitrite concentration begins to climb. After one week, in sync with ammonia testing, begin testing nitrite concentration, measuring once every two days. Nitrite will peak and then slowly decline.

After about two weeks, it begins to enter the later stage. After another week, when both nitrite and ammonia concentrations have dropped to zero, the nitrate concentration begins to increase. At this time, congratulations, the system has been established. Do not rush to add more fish. First do a small water change, then wait two more days, then add fish again. Do not add more than three at a time, otherwise, if too many are added at once, the system will collapse, and the efforts of the previous three weeks will be wasted.

During the first week, nitrifying bacteria liquid can be added, which also helps. If you are lucky, it can shorten the time by one week. The first month of fish keeping is the critical period. It is a test given to us by heaven, to see whether we truly want to keep fish or are just playing around.

I know that if a newly bought fish tank only has two or three fish, can it really look good when it is so empty? But trust me, take it slowly, and the fish will thank you.

Having finished talking about cultivating nitrifying bacteria, below let us talk about the growth environment of nitrifying bacteria.

1. Temperature

The suitable temperature for nitrifying bacteria is about 20~28 degrees, and the most suitable temperature for growth and reproduction is about 25 degrees C. Generally, nitrifying bacteria stop metabolism below 5 degrees and above 42 degrees. Beyond this range, ordinary nitrifying bacteria find it very hard to survive.

2. Light

Nitrifying bacteria, unlike green plants and certain autotrophic photosynthetic bacteria, generally do not have photosynthetic pigments, so they cannot use sunlight to carry out photosynthesis and synthesize organic matter. Not only can they not use sunlight, they are actually afraid of sunlight exposure.

3. Substrate

Nitrifying bacteria greatly need substrate, but unlike others, their purpose is not to seek food. Instead, substrate can provide attachment, shelter, and access to the ammonia source and nutrient source they need. Many nitrifying bacteria cannot reproduce before finding suitable substrate, and cannot use ammonia sources and nutrient sources.

4. Water flow

Because of the attached lifestyle of nitrifying bacteria, water flow must transport the oxygen, ammonia, nutrients, and other survival resources they need.

5. Dissolved oxygen

Dissolved oxygen is an indispensable living element for nitrifying bacteria. It is recommended that it not be lower than 2ppm.

pH value: Generally speaking, the vast majority of nitrifying bacteria prefer to grow in weakly alkaline water, with a pH of about 7.5~8.2. pH value affects the growth and reproduction of nitrifying bacteria. The pH range for Nitrosomonas bacteria is 7.0~8.0, with the best average being 7.8. The range for Nitrobacter bacteria is about 6.5~8.5.

6. Competitive exclusion

This refers to the living space of nitrifying bacteria being squeezed by other heterotrophic bacteria, causing the nitrifying bacteria population to be unable to continue developing, and even tending to gradually shrink. Organic pollution not only affects the growth of nitrifying bacteria, but also attracts heterotrophic bacteria, forcing them to have no choice but to evacuate their home and search elsewhere for development.

That is all for today's content. I hope this article can help everyone. If there are any shortcomings, I still hope all the seniors can offer guidance!

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