Why and How Should You Seed a New Aquarium?

Goldfish Swimming In Aquarium

It's becoming fashionable to seed a new aquarium. It is the process of moving nitrifying bacteria from an existing aquarium to a new one. Seeding the aquarium gives it a head start on the cycle process. In a fresh aquarium, it usually takes 4 to 6 weeks for beneficial bacteria to complete the nitrogen cycle. Seeded aquariums are known to cycle in half the time they would typically take, allowing you to supply the new tank with more fish sooner. Seeding also lowers or eliminates fish loss throughout the starting cycle, reducing stress on the fish.

Where the Bacteria Live

Contrary to popular belief, considerable numbers of are not found in the water; rather, they are attached to tank surfaces. As a result, moving water from an established tank will be ineffective. The majority of live in gravel and filter media (ceramic rings, filter floss, sponge, etc.). The bacteria may also be found in porous surfaces such as rocks, artificial plants, and other materials.

Aquarium Seeding Material Sources

The difficulty of obtaining seeding material is one of the reasons why many people do not seed their new aquariums, although there are various methods for getting some. Seeding material is simple to get if you already have at least one tank going. If you don't have another tank, consider the following options:

  • Local fish stores (LFS): Fish shops may accommodate a customer's request for seeding material.
  • Fish clubs: Any fish club worth its salt will assist a new fish owner by providing seeding material.
  • Friends: If a friend has an established tank, simply ask them for some.


When procuring seeding material from an established aquarium, be sure that there are no diseased fish in the tank. You don't want to bring bad bacteria or parasites into your new aquarium!

Transporting Seeding Material

To keep the bacteria alive, seeding material must be moved quickly from one tank to another. Set up the new tank and let it run for a day to settle the temperature and water chemistry before transferring seeding material. After that, obtain your seeding material and start using it within an hour.

Keep the material covered with a tiny amount of water from the original tank throughout transit (the source of the seeding material). Avoid exposing it to extremes of temperature and transfer it as fast as feasible. Because nitrifying bacteria need oxygen in the water to exist, allowing seeding material to sit for more than an hour might kill them. If the material has been exposed to high heat or cold, it should be discarded and replaced with new seeding material.

Seeding With Substrate

Seeding a new aquarium with substrate from an existing aquarium has two options. The first is to simply spread the seeding substrate on top of the substrate in the newly set up aquarium in an equal layer. If the substrates are comparable in color and size, this technique works effectively.

The alternative approach involves a nylon pantyhose bag. Fill the toe of the hose with 1/2 to 1 cup of substrate, knot it off, cut it from the remainder of the leg, and hang it all in the tank. Remove the bag and discard it when the tank has cycled (or you can use it to line the bottom of a potted plant; the substrate allows excess water to drain from the soil, and the debris from the aquarium makes good fertilizer).

Seeding With Filter Media

Filter media works well as a seeding medium. To employ this approach, just add an extra filter to an existing tank for a few weeks to allow nitrifying bacteria to develop on the filter material. are suitable for this since they are compact, low-cost, and portable. Filters such as power or even canister filters can be employed.

The seeding filter may be moved from the established tank to the new tank once the new aquarium has been set up and operated for at least a day to stabilize the temperature. Keep the seeding filter running until the new aquarium has completed its cycle. You may keep it in situ forever if you want to use it as seeding material in the future. If the necessity arises, it may also be utilized to swiftly set up a hospital tank.

Use fresh filter media (ceramic rings or a sponge) intended for use in the new aquarium filter as an alternative. Before setting up the new aquarium, place the media in a mesh bag and put it in the existing tank for a few weeks. This will encourage the growth of nitrifying bacteria in the medium. Remove the bag from the established tank and immediately insert the wet media in the new filter once the new aquarium has been filled and the filter has been fitted. This will kickstart the new biofilter with beneficial bacteria that have developed in the media while it was in the old tank.


There are also several helpful bacteria supplements and "bacteria starters" available at pet stores that will speed up the nitrogen cycle in a fresh aquarium. When these boosters are added to the seeding material, the time it takes for a new aquarium to grow a mature biological filter is reduced. This reduces the possibility of "New Tank Syndrome," which occurs when fish create poisonous waste quicker than good bacteria can break it down and make the aquarium water healthy for the fish.