Establishing a New Aquarium

An aquarium is more than a container for fish and water.  It is, ideally, a (fairly) balanced ecosystem containing many organisms and processes, most of which are microscopic or invisible.  Try to think about "establishing" a new aquarium as giving the tank the time and conditions for all those processes to start working and doing what they should do.  This article suggests a way of doing that "naturally", without too much in the way of chemicals or expensive gear.  

The real basics of aquarium keeping are mostly about water quality and they apply to all aquariums - tropical freshwater, coldwater, marine or planted aquascapes - and of any size, from "nano" cubes to giant public aquaria.  They even apply to ponds and "sea world" theme parks.  We'll talk about equipment and tank setup in the next article, but there's one thing we need to discuss first.
The most important thing in aquarium establishment is waste management.

Your suburb or town would turn pretty nasty pretty quickly if the sewerage system failed, even if it did have lovely gardens and theatres.  You aquarium is the same - we need that "basic infrastructure" before we can make it a nice home.

Remember that every living thing in your tank - the fish, snails and even plants - will be producing liquid, solid or gaseous waste products from day one.  In an environment as small as a home aquarium, those waste products would build up to toxic levels very quickly, even with the best aquarium filters in the world, if it wasn't for some very special micro-organisms.  These are the bacteria that convert the toxic parts of biological waste to less toxic and even useful chemicals.  

The number one enemy of fish and fishkeepers is ammonia

A basic component of all biological waste.  But first you have to get some in your tank - yes, that's right, you need some ammonia.

There are bacteria in every natural body of water (and soil) that convert ammonia to another chemical - nitrite.  But nitrite is enemy number two - it is also toxic!  Luckily for us (and for all life on earth) there are also bacteria that convert nitrite to nitrate - a far less toxic chemical.  The problem for aquarium keepers is that the process of establishing sufficient colonies of these bacteria in a new aquarium (or filter) takes time.  The whole process is called the Nitrogen Cycle and the establishment of the necessary bacteria in a new tank is referred to as "cycling".  This is why the trained staff in specialist aquarium shops advise you to give a new tank a few weeks to "settle" before adding fish.  Some people might also advise you to use certain products to "seed" or "accelerate" the cycling process or to neutralise the ammonia and nitrites so you don't have to wait to add fish.  Honestly, the jury is out on whether these products do what they say and whether they do really lead to a fully operating nitrogen cycle even in the long term.  

The only "neutraliser" or "treatment" you really need is one that deals with the chlorine (actually its chloramine now days) that is added to our water supplies to kill bacteria.

Most experienced aquarium keepers have their own methods to kick start and hasten the nitrogen cycle in a new tank.  Most will involve one of the following strategies:
  • "seeding" the tank with water, gravel, plants and even filter detritus (the technical term is "gunk") from a well-established aquarium.  This ensures that the necessary bacteria are there in decent numbers from the beginning.  Just using a filter from an "old" aquarium is a favoured way to do this; AND
  • either starting the tank off with just a couple of very robust fish that can poop out some ammonia and still live through the peak periods of ammonia and nitrite build-up; OR
  • adding a non-living source of ammonia to the new tank to give the bacteria something to feed on - this can be a sprinkle of fish food, a small piece of raw fish meat or prawn or even a few drops of "pure" ammonia (not the "cloudy ammonia" used for cleaning)

Whichever way you do it, it  really is worth waiting for at least four weeks before adding any delicate or valuable fish.

Do set up your tank with its heater (if tropical) and filter but then be patient.  A light at this stage is optional and probably better left off.  You can get test kits for ammonia, nitrite and nitrate and follow the course of the cycling by testing the water every few days until there have been definite peaks of ammonia and nitrite before they both fall to zero and nitrates rise to around 10 parts per million (ppm).  The tank is then "cycled".

Once the tank has "cycled" you should do a big (50% to 90%) water change (using the chloramine neutraliser for the new water) before adding any fish.  Or you can just wait four weeks, do the water change and introduce new fish a few at a time.  The more times you set up a new aquarium, your understanding and "feel" (and respect) for the nitrogen cycle will grow.  

We'll talk about the reasons for changing a proportion of your tank's water occasionally in another article.  Basically, you are diluting the residual nitrates to keep them below levels where they may cause discomfort to fish.

Filtration really helps maintain the nitrogen cycle by providing water movement across the bacteria on the tank walls, the gravel and rocks and the plants. Importantly, a filter provides additional substrate for bacteria to attach on to.  The larger the surface area of the filter medium (foam blocks, ceramic tubes, plastic watzits etc.), the faster and better the bacteria will establish and the more fish your tank can support in comfort.  The rate of water flow in the tank and the filter does not need to be particularly strong for the bacteria to operate at peak efficiency.  Filters also help by trapping and concentrating solid waste, but this is always a secondary function.  Whatever type of filter you choose (and there are many), have it working from day one, don't turn it off and only "clean" it by rinsing the gunk out of the foam or other medium gently in a bucket of tank water - those bacteria are delicate and valuable!

Something to be aware of during this "running-in" period is that you will probably get some algae growth on the glass and gravel.  A bit of that is fine.  The brown stuff is actually not algae but another type of microorganism called Diatoms that thrive in these conditions.  It will most likely dissappear of its own accord soon after the cycling completes and the tank goes through an additional period of settling in over the next two months.  If green algae does start to grow very actively, reduce the number of hours the light is on each day.  You can do a clean up before you add fish and plants. 

Aquarists disagree about whether you should establish aquatic plants in a tank while it is still "cycling".  Plants will not be harmed by the levels of ammonia and nitrite reached and may benefit from both.  The real issue is whether or not they will out-compete the bacteria for the available ammonia and therefore delay proper cycling.  Remember, at this stage we actually want ammonia in our tank as food for our friendly bacteria.  A few plants will not hurt at all but it might be best to avoid adding lots of fast growing plants until you are sure that a cycle is well underway.  At that stage, the more plants you have, the lower your ultimate nitrate levels will be.  You have to bear in mind, however, that plants also need appropriate levels of light and carbon dioxide, as well as those nutrients in the water.  We'll cover aquatic plants in another article.

Waiting for a new tank to cycle is hard, especially if you have, or are, a kid (or an adult male who failed that part of adolescence where you are supposed to develop impulse control).  But that wait can be the difference between a successful, enjoyable aquarium and a slowly unfolding disaster.  Buying some lovely fish and setting up a tank for them, only to see them die off one by one over a period of a few weeks as the ammonia and nitrites kick in, is very disheartening and often the end of promising hobby or great home decor idea.  More aquariums fail because of inadequate "cycling" than for any other reason.  One way around the agony of waiting for a new tank to cycle is to set up a new tank a week or so before you go on holiday.  That way the stocking of it can be a treat for when you get home.  A holiday and a new fish tank!  What could be better?

The nitrogen cycle can get broken if you accidently kill off the bacteria by doing something like really cleaning your filter (say, with hot water or the garden hose) or using a "fish medicine" that kills bacteria (and some of them do, believe it or not).  Adding a lot of new fish at one time can also mean that the bacterial populations are lagging the rate of waste production.  Do more water changes if this happens to you.  As in most things to do with managing aquariums, slow and gentle change is the safest policy.

Apart from a chloramine neutraliser, the only additional chemicals or treatments you might need are:
  1. a simple "pH buffer" to stop our "soft" water becoming too acidic ((in Canberra and Melbourne particularly).  Commercially available products for this are OK, but the same result can be achieved with coral sand at a teaspoon per 50 litres for the tank - this will buffer the water for several weeks (just add it onto the gravel).  If you are intending to keep fish from very alkaline environments (eg. the "Rift Lakes" of Africa) or from slightly salty areas (eg. Mollies and some Australian native fish), you should do a bit more research on their needs (or move to Adelaide!).  However, these special conditions can usually be achieved with coral sand (carbonate) and a few commonly available salts (like non-iodised ordinary table salt and Epsom salts).
  2. a "stress coat" product to use when you are adding new fish to the tank.  I (the author) don't use them and have no idea what they are or whether they "work" or not, but several fish-keepers I have a lot of respect for say they are Good Things.
Things like plant fertilisers can come later - much later, in fact.  If you are in a regime where you are adding several drops of this or that every couple of days to an aquarium that is less than three or four months old, you should put those potions back in the cupboard for a while and let things take their own course.   The use of "activated carbon" in aquarium filters is also no longer recommended by most authorities except in very special circumstances - and certainly not during cycling (although many filters still come with a cartridge or bag of carbon that you are supposed to replace on a regular basis).  

On the whole, the most important things you can add to your first aquarium are 1) Time (to cycle) 2) Knowledge (about what is happening invisibly) and 3) Observation (to check that everything is going OK).  

After the cycle is established, keep things steady - no wild swings in temperature or lighting times - regular partial waterchanges - moderate feeding of the fish, removing dead plant leaves, gently cleaning the filter now and again and wiping any algae buildup off the glass.  A simple consistent regime will do more that a hundred dollars worth of chemicals.  Much better to spend your money on some nice fish or plants - or on joining your local aquarium society - than on treatments or equipment that may not be really needed.