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New Tank Syndrome: Learn to Diagnose, Cure, and Avoid it

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If you love fish, setting up your new home aquarium can be exciting because you’re adding new life to your home and also are able to create a unique tank setup due to your liking. However, moving fish into a new aquarium can cause some problems if you are not prepared. 

New tank syndrome is a disease common in fish that is caused by an increased amount of ammonia in a new (sometimes old) tank. It commonly occurs when a tank is between 1 to 20 days old and lacks any beneficial bacteria in the tank. There are several causes, but the problem can be avoided. 

To have an optimum new tank, you will need to be knowledgeable on what new tank syndrome is, how to diagnose the problem, how to cure the problem, and how to ultimately avoid the issue altogether. We have the answers to what you’re looking for! 

New Tank Syndrome: What is it? 

New tank syndrome is essentially a lack of nitrifying (good) bacteria in your fish tank that can convert ammonia to nitrate. As most aquarium enthusiasts know, ammonia is highly toxic to fish and can kill them very rapidly.  So what do these good bacteria actually do?

This all has to do with the aquarium nitrate cycle. Typically, the fish waste in your tank will turn into ammonia. The good bacteria will then convert this ammonia into nitrate, which then again turns into nitrate. This nitrate is then removed from the tank during water changes. 

Seems simple enough, but again, when there is a new tank set up, there can sometimes be a lack of the good bacteria which causes all of that ammonia to skyrocket. The fish will then die due to ammonia poisoning. 

Beautiful planted tropical freshwater aquarium with fishes

Common Signs of New Tank Syndrome

There are a few telltale signs to look out for when it comes to new tank syndrome. If you notice any of these signs you should take action immediately to try and prevent any deaths.

  1. Many fish have died without warning very suddenly. If you have a large tank with a lot of fish, it can be common to lose a fish here and there without warning. However, if you are noticing multiple fish die in a short time, this can be a cause for concern. 
  1. Frequently cloudy and smelly aquarium water. If you notice that the water in your tank has frequent cloudy bursts and has a dirty smell to it; this is the ammonia waste buildup. 
  2. Lack of appetite in fish. If you notice more waste in your tank and your fish not eating as much, this can be a sign that there is too much ammonia in the tank.
  1. As such, a pale fish that seems lethargic and not moving too much in the tank can also be a sign of new tank syndrome. 
  1. Gasping for air. If you have a great filter and a bubbler, a fish gasping for oxygen at the top of the tank can mean the tank is too riddled with ammonia to breathe.

The Causes of New Tank Syndrome 

While we did mention that the more immediate cause for new tank syndrome is the lack of good bacteria and the nitrate cycle being “off”, there are a few other causes as well. 

  • Overfeeding of fish: leads to more waste in the tank.
  • Too many fish in the tank. If you have an overcrowded tank, this could be a recipe for disaster and lead to too much ammonia. 
  • The tank is too clean. You may be thinking, “the tank needs to be clean in order to remove the ammonia”. While this is true, it is best to do partial cleans in a tank and not full water changes. This will remove some nitrates, but will allow good bacteria to grow as well. 
  • Chlorine. When adding new water, it is important to follow the dosage of tank solutions to properly dechlorinate the water. If there was not enough solution put in the tank, chlorine can be left behind and will also lead to ammonia.
  • Sudden changes in water temperature. If you have tropical fish that need to have a warmer environment and then suddenly a heater stops working,the temperature can drop rapidly. This quick drop can cause the cycle to offset and ammonia to build up.
  • New decorations or gravel. It is important to make sure that all new gravel and decoration are properly cleaned. Again, if not this will cause ammonia to build up. You can do this by rinsing all new decorations and gravel with very hot water, or by using a bit of vinegar and scrub brush as well. Just make sure to rinse the vinegar thoroughly. 

How To Cure New Tank Syndrome

If you notice any of the common signs of new tank syndrome, the first step you can take is to use a water testing kit to test the ammonia and nitrate numbers in the tank. Keep in mind that new tank syndrome can last between 2 to 12 weeks. If they are on the high end, you will need to take action immediately. 

  • Complete frequent water changes. As previously stated, you do not want to do a complete water change, but rather 25% of the water one a week. This will remove some of the toxic waste, but will also dilute the ammonia and nitrate currently in the tank. 
  • Underfeed your fish. While this may sound awful, it is actually great for your tank. Since there is already a ton of waste, you will want to decrease this waste by feeding your fish less. Once the situation is under control, you can then begin feeding as you typically would.
  • Add good bacteria. Thankfully, there is a tank solution that will add good bacteria back in your tank immediately. You can find this at most aquatic stores, but again, make sure to follow the instructions to the tee that are on the bottle. 
  • Add an air stone or bubbler. The biggest problem with new tank syndrome is the lack of oxygen in the tank due to excessive ammonia. This is what immediately kills the fish. To help this, you can add a bubbler which creates air flow in the tank and ultimately adds more oxygen.
  • Change filters frequently. With all of the toxic waste in the tank, you will want to ensure you keep your filter clean so it can do its job. While filter changes are recommended monthly, you can increase this to every week until your tank returns to a healthy environment. 

How to Prevent New Tank Syndrome 

It is obviously best to try and avoid new tank syndrome altogether. While these tips may not always work, they are the best shot at preventing any illness in your fish.

  • Allow your tank to cycle for a few weeks prior to adding fish. This won’t work if your tank is already established, but if you have a new tank you will want to set up the tank with freshwater and a dechlorinator a few weeks before adding any fish. Use testing strips weekly to verify the proper parameters before adding fish.
  • Only add a few fish to the tank at a time to prevent overcrowding and fast bacterial growth.
  • Never overfeed your fish because it will add more waste.
  • Make sure there are bottomfeeders in the tank to take care of excess waste including plecos, or catfish. 
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