New tank syndrome is the term people use to refer to unexplained death of fish in an aquarium that is new, or under 3 months of life. Most cases of new tank syndrome can partially be blamed on inexperienced aquarist, but even people who have had aquariums for years lose some fish to this at some point. Thankfully, avoiding new tank syndrome is not so difficult.
Most fish who die on a newly set up aquarium do it due to ammonia poisoning, caused by an improperly cycled aquarium. Ammonia is a by-product of animal waste such as fish waste, uneaten food, and the odd dead fish that hasn’t been removed soon enough. Ammonia is highly toxic to fish, but naturally occurring nitrifying bacteria will transform it into nitrites, and eventually into nitrates that are much less toxic and can be removed from the tank through regular water changes.
However, for this to happen bacteria need to have a chance to establish themselves in the aquarium before fish are introduced and ammonia starts being generated in large amounts. Unless you have enough bacterial population to deal with all the ammonia and nitrites, your fish will suffer from ammonia stress that can kill them, or at the very least make them susceptible to diseases that will kill them.
How to fix ammonia poisoning on your aquarium? Easy. Cycle your tank before you add fish, or with some very hardy fish and careful monitoring of the water conditions, and frequent water changes.
Sudden Changes In Water Parameters
Seemingly minor changes on water parameters such as pH or temperature can have terrible consequences on an aquarium if they are very sudden. Fish need time to acclimate to new water conditions, and sudden changes are one of the main reasons for fish stress after purchase. This is even more true on a marine aquarium that requires more stable water conditions than a freshwater one.
Try to avoid sudden changes in temperature by always using water that is at a similar temperature to your aquarium for water changes, and properly conditioned with an aquarium water conditioner. In order to give your fish the best possible environment, it is very important that any changes to the aquarium are done gradually. For example, if you need to raise the aquarium pH using chemicals do it over a few days
Overstocking The Tank
Adding too many fish, or adding them too quickly, can throw your carefully cycled biological filter totally off-kilter. This means your tank will enter a mini-cycle until the bacterial colonies grow enough to maintain the new population. Until that mini-cycle is done, your fish will be subject to the perils of cycling, including ammonia poisoning. To avoid this, increase the number of inhabitants of your tank slowly and gradually. Add a few fish, test the water parameters over a few days, and don’t add more fish until everything is stable and there is no ammonia or nitrite to be seen.
Depending on the strength of your filter and your water changing schedule, your tank will be able to sustain a determinate amount of fish and living organisms. This is known as bio-load. You can help increase your tank’s ability to sustain life by planting (plants generate oxygen and remove ammonia pretty effectively) but fish will also require space to swim and many fish are territorial to a point. An aquarium with few, well chosen fish that are active and happy is considerably more attractive and easier to maintain than an overstocked tank.
Inadequate Water Testing And Maintenance
It is important to get familiar with your water testing kit even before you buy any fish. In fact, running tests during the cycling period is necessary in order to identify the different stages of the cycle. Testing regularly should avoid creeping water parameters changes, such as a piece of non-aquarium safe decoration dissolving and affecting your water chemistry, or excess rotting food increasing the nitrites.
Most fish won’t suddenly die if the water chemistry is off. Instead, they will become stressed. Stressed fish are more sensitive to sickness and parasites such as Ick. Other causes of stress are aggressive tankmates, an environment lacking places to hide, inadequate food, etc… So while you may think that your fish just caught some disease chances are readjusting the aquarium conditions can put them in the way to recovery even before you start medicating them.
Too few water changes can cause algae bloom (due to excess nitrates) and will also stress out your fish. However, be careful not to go overboard and cause new tank syndrome by changing too much water at the same time. Some fish are very sensitive and require frequent but minimal (10-15% water volume) water changes every week.
Correctly balancing an aquarium water chemistry is key to a thriving, algae free, happy fish tank.
Getting The Wrong Fish Stock
Each kind of fish has its own favourite environment, and while most fish will adapt (particularly hardy freshwater fish) this doesn’t mean that you should forget about this when planning your aquarium. Not to mention some fish will not be suitable for community aquariums, while others will require lively tankmates in order not to become the biggest bully in the tank. There are many different types of aquariums and in order for your fish not to be stressed out the right tankmates are a must.
Never go into a fish store without a researched list of which fish you want to buy. Otherwise you will end up with fish that are incompatible with the tap water values on your zone, or even more likely, with fish that will do their best to kill each other. While many fish stores will endeavour to rehome unwanted livestock, if you avoid buying incompatible fish in the first place it will save you money to start with.
Most of the causes for new tank syndrome relate to water quality and inadequate maintenance, but it is easy even for an experienced aquarist to make a mistake, particularly in small aquariums. Large aquariums are generally more novice-friendly because the larger volume can buffer the tank against sudden water changes. Careful monitoring of your aquarium until it’s fully established is the best way to prevent new tank syndrome.