The most common fish deaths are a result of ammonia or nitrite poisoning, in which the biological filtration has not been well established. The nitrogen cycle turns fish wastes to ammonia (which is toxic), then nitrite (still toxic), and finally, nitrate (not toxic in low concentrations).
Ammonia poisoning resulted from incomplete nitrogen cycle or no filter at all, shock from sudden change in water temperature and (or) water chemistry, overfeeding. These are the leading causes for fish dying in a fish tank. In fact, the average life span of fish sold in the U.S. is only 3 weeks. Nitrogen cycle is the most important of them all, since it is unknown for most new fish keepers.
Respiration. Also, if the fish die, they slowly return the nitrogen to the air.
Two sources of bacteria that contribute to the nitrogen cycle in a fish tank are Nitrosomonas and Nitrobacter. These bacteria play a crucial role in converting ammonia to nitrite and then to nitrate, which helps maintain water quality for the fish.
Nitrogen Cycle occurs in the aquarium.Fish produce ammonia which is toxic. In a well established aquarium, Some beneficial bacteria will break down the ammonia into nitrite, and a second species of bacteria will break down nitrite into less harmful nitrate. The whole process of converting ammonia into nitrite and then into nitrate is called nitrogen cycle.Although, only well established fish tanks have this nitrogen cycle going normally.For new aquariums, fish keepers must do fishless nitrogen cycle before they add any fish at all, or the fish will risk dying to ammonia poisoning due to insufficient amount of good bacteria. The whole fishless nitrogen cycle process can take 6~8 weeks.
If you refer to the cycle of an aquarium, it means a nitrogen cycle. Fish produce ammonia as natural waste, and it is toxic which will harm and kill themselves. In those well established tanks, good bacteria are in sufficient number to break down ammonia into nitrite, then convert nitrite into nitrate which is much less harmful. New fish tanks do not have enough of these beneficial bacteria. Thus, experienced fish keepers will do a nitrogen cycle before they add any fish at all. The safest and the most popular way to cycle a fish tank these days is to cycle the tank without any fish. It is called Fishless Nitrogen Cycle. In a Fishless Nitrogen Cycle, the best and fastest way to do it is to use pure ammonia. You just need to keep a constant source of ammonia on daily basis and wait for the bacteria to grow into sufficient number. The whole process can take over a month. You will need a water test kit for the fishless cycle. Once your test kit reads 0ppm for both ammonia and nitrite after you have added ammonia on the same day, your fishless nitrogen cycling has completed.
Only if you have a toxic Nitrogen Cycle.
If you are trying to do a nitrogen cycle, do not use that product. It will not aid your cycle of the tank. Many of such products have the wrong type of land based bacteria which will die in the water after just a week, and your seemly completed cycle will crash in that moment.You need to do a fishless nitrogen cycle. It will grow the correct type of water based bacteria to take care of your fish's ammonia.
An established aquarium is an aquarium that has gone through the nitrogen cycle. This is not "established" it is a "cycled" aquarium. The stage after cycling where the plants are reproducing and fish are growing successfully is an "established" aquarium. See related question on the nitrogen cycle.
They provide hiding places for the fish, they will take in Nitrates completing the Nitrogen cycle, and they look nice!
Yes, fish poop can serve as a natural fertilizer for aquarium plants. The waste produced by fish contains nutrients like nitrogen and phosphorus, which can be absorbed by plants to help them grow. This process is known as the nitrogen cycle in aquariums.
Yes, fish fertilizer does contain nitrogen.
Ammonia is harmful to fish. Its is a by product of the nitrogen cycle, which is what keeps the water stable in your tank(i wont delve into that) but yes ammonia can burn fish, especially those who lack scale's.