New Tank Syndrome: This is quite simply the most frequently seen mistake in the saltwater aquarium keeping universe; in the form of dead or dying fish that (mostly) beginners to the hobby make.
The root cause behind New Tank Syndrome (NTS) is a lack of patience: wanting to see those pretty fish swimming around well before the aquarium water has chemically “cycled” to a point where the beneficial bacterial populations can cope with converting this fish induced ammonium waste to the less harmful nitrite (courtesy of Nitrosomonas bacteria) which is then converted to the much less harmful nitrate (courtesy of Nitrobacter bacteria).
This NTS will manifest itself as very stressed ammonium/nitrite toxified fish gasping at the surface, red colouring around the gills, diseases appearing due to stress or fish may even die with no symptoms. At this time many newbies give up in distress and leave this amazing hobby, if only they had read this article first…
This nitrogen cycling or “break in” process takes time, typically with NTS too many fish tend to get put into the aquarium way before the bacteria are present in sufficient numbers to cope with their waste products, this mistake can occur from any time after the initiation of the nitrogen cycle with an ammonium source (use a commercial product and follow the instructions) to the cycling process being almost, but not quite complete.
Cycling can take anyway from 3 to 100 days depending on what sort of filter (seeded or unseeded) you are using and whether or not you have live rock/sand. The key to not making this expensive mistake is regular ammonium, nitrite and nitrate testing using good test kits to see which phase the cycling is in before you add your first fish (I say first because using living fish to initiate the cycling process is cruel).
You will want to see zeros levels of ammonium and nitrite (which you should have noticed have spiked and then come down over time) coupled with increasing levels of nitrate; which can be gotten rid of with regular partial water changes before the first fish goes in.
If you are reading this too late in a panic because all your fish are dying, it may not be irreversible. You can potentially save your fish by conducting a series of water changes (same temp, specific gravity pH) etc or moving your fish to a quarantine tank. You can also use products like Amquell to reduce ammonium levels and try adding some activated carbon to the system. Your fish if you can save them will be very stressed with weakened immune systems, adding some methylene blue to the water can help avoid infection.
New Tank Syndrome does not just happen to gung ho newbies you know. If you damage the bacterial population in your not-so-new aquarium by physically removing or chemically treating (many medications and antibiotics will kill beneficial bacteria) you will have exactly the same problem. This also goes for severe shock caused by massive temperature fluctuations and the use of chlorinated water.
So the moral of this story is to not be one of the uneducated masses that pour into and out of this hobby; be mindful of your bacterial helpers, test regularly during the cycling process and most importantly move slowly.
Happy marine aquarium keeping,
Marine Aquarium Maestro
Saltwater Aquarium Advice