Do I need to cycle my aquarium before purchasing a seahorse?


Yes, ensure that your saltwater aquarium is fully cycled (operating for at least 4 weeks) BEFORE adding seahorses. When fully cycled, beneficial bacteria in your aquarium are actively working to biologically filter the water - naturally breaking down and converting toxic fish waste from the aquarium water into by-products less harmful to fish. 

Basics on the Nitrogen Cycle:

The nitrogen cycle is a biological process where aerobic bacteria breakdown ammonia into nitrites - and nitrites into nitrates. An overview of the nitrogen cycle:

  • Fish waste and uneaten food break down to form ammonia (NH3/NH4). Any level of ammonia is toxic to fish.  Ammonia begins to rise to toxic levels after about three days after introducing fish.
  • Beneficial bacteria oxidize the ammonia and create a by-product, nitrites (NO2). Nitrites are also toxic to fish in small amounts. When an aquarium is cycling, nitrites begin rising by the end of the first week after introducing fish. 
  • In the last stage of the cycle, beneficial bacteria convert the nitrites (NO2) into nitrates (NO3). Nitrates are not highly toxic to fish in low levels (under 20 ppm).  It takes about four weeks to complete this cycle and reach this last stage.  After that, the nitrogen cycle will continue to break down waste in the aquarium water without harmful spikes in ammonia and nitrites.  Routine partial aquarium water changes must still be done to keep the nitrate levels within a safe range.

Basics on How to Get Started:

  • When setting up aquarium, add natural products (live rock and sand) and/or biological filter media. The rock/sand/media provide a surface for the bacteria to grow.  Purchase live rock and/or sand that already has active bacteria to speed the cycling process.
  • To speed up the cycling process further, you can also add a bioculture to introduce beneficial bacteria into your tank. We use Brightwell Aquatics MicrōBacter7 bioculture that is formulated to establish this biological filtration in new aquarium set-ups.
  • Purchase and introduce several durable, inexpensive fish into your aquarium to provide ammonia to start the cycling process.
  • During the cycling period, test your tank water chemistry for ammonia, nitrite and nitrate levels. When testing shows ammonia and nitrites at 0, your tank has cycled and you are ready to slowly add more fish, including seahorses.

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