4 Ways To Cycle A Fish Tank

This method requires a lot of patience, as it requires you to wait for the organic material you add to your tank to decay and start producing toxic waste products. However, it’s often considered a more “humane” option as it doesn’t expose fish to ammonia and nitrites like the method above does. [2] X Research source

Once you detect nitrites, you’ll know the cycle has started. At this point, you’ll continue adding ammonia as you have before.

You can detect this final phase of the cycle by either testing for nitrites (in which case you’re looking for a sudden drop), nitrates (in which case you’re looking for a sudden spike from a base level of zero), or both.

However, as in the method above, you’ll want to add your fish gradually. Don’t add more than a few small fish at a time and wait at least a week or two before introducing your next batch of fish. Consider cleaning the substrate with a siphon hose before adding fish, particularly if you had to add a lot of food. Decaying food or plant matter can become a ticking time bomb. If it gets trapped in the gravel, the ammonia won’t enter the water, but if something upsets it, it could release a fair amount of ammonia rather quickly.

Assemble the aquarium Add substrate Add water Add air stones, air pumps, etc. Add plants, rocks, etc. Add filtration system (and/or protein skimmer) Add heater

White Clouds Zebra Danios Cherry or Tiger Barbs Pseudotrophius Zebra Banded Gouramis X-ray Tetras Pupfish Most minnows Most guppies

Fish who eat more produce more waste, which can cause the levels of toxins in the tank to rise before the bacteria have a chance to colonize the aquarium. Leftover food will eventually rot, producing toxins on its own.

Don’t use chlorinated water — this can kill the bacteria in the tank, forcing the cycle to start over. If using tap water, make sure to treat it with an appropriate dechlorinator or water conditioner before adding it to your aquarium. If using bottled water, make sure to buy distilled water, as “purified” or “drinking” water may have minerals added for taste that may be harmful to fish. Be ready to perform water changes much more frequently if you start to see signs of serious ammonia stress in your fish (more information below in the “Solving Common Problems” section. ) However, try to avoid stressing the fish by exposing them to big changes in water chemistry or temperature.

You will want to keep ammonia levels below 0. 5 mg/L and nitrite below 1 mg/L throughout the cycling process (ideally, they should be less than half of these values. ) If these chemicals start to approach unsafe levels, increase the frequency of your water changes. The cycling process is complete when both ammonia and nitrite levels drop so low that they are undetectable. For practical purposes, this is often referred to as “zero,” though this isn’t technically accurate. As an alternative, you can take water samples to the pet store where you bought your fish or aquarium. Most will offer cheap testing services (some even do it for free!)[6] X Research source

After each addition of new fish, wait at least a week or so, then test the water once more. If ammonia and nitrite levels are still low, you may add your next few fish.

Try to use filter media from a tank that’s a similar size and has a similar amount of fish. Mis-matching your filters (like, for instance, using a filter from a tank with just a few fish in it to cycle a tank with a greater number of fish) can leave you with greater loads of ammonia than the bacteria are able to process right away.

Fast-growing plant varieties (like, for instance, Vallisneria and Hygrophila) tend to absorb the most ammonia. Floating plants also generally work well.

Pests that can be transferred this way include snails, harmful algae, and parasites like ich and velvet.

Be sure to use certified aquarium salt — table salt isn’t formulated for your tank and may hurt your fish.

Lethargy/lack of movement (even when food is added) Refusing to leave the bottom of the tank Gasping for air at the surface of the water Inflamed eyes, gills, and/or anus.

Some people believe that ammonia removers can be harmful in the long-run. [8] X Research source This may be due to a misunderstanding of the process of detoxifying. In a tank, toxic ammonia (gas NH3) is in reversible equilibrium with not-so-toxic ionized ammonia (NH4+). Most of the detoxifier products convert toxic ammonia into the form that isn’t so harmful to fish. However, after 24 to 48 hours, they will release the ammonia. That’s why these products should be used: as long as the useful bacteria is not yet established AND, from time to time make a partial water change (as per manufacturers’ instructions) to remove some of the ammonia accumulated[9] X Research source AND even if is not specified, dose the detoxifier for the whole tank, not just for the new added (replaced) water, as the already bonded ammonia in the tank will be released soon (after 24-48 hours from previous dose). Changing 50% of the water (or more) generally prolongs the time required to cycle the tank (or even stop the cycle) just because the useful bacteria will be temporary inhibited and will need time to adapt to new pH. [10] X Research source Book: “Nitrification and Denitrification in the Activated Sludge Process”/Michael H. Gerardi . For this reason, some recommend a pH change of less than 0. 2-0. 3 per day. Suppose you have 7. 8 pH in tank, replacing 25% with water of pH=7 will bring the final pH to 7. 6. Useful bacteria transforms only ionized (non-toxic) form of ammonia, so they benefit from these products also. [11] X Research source .

In addition, modern goldfish are somewhat susceptible to diseases that can easily spread through the entire aquarium. [13] X Research source You won’t want to cycle any aquarium with so-called “feeder” goldfish, which are poorly-cared for by breeders and sellers and are extra-susceptible to disease. [14] X Research source