Home Aquariums

A lot of newbie aquarists buy a tank, throw in some water and fish, sit back and 3 or 4 days later wonder why their fish are all dead. This is a scenario that happens so often it has its own name - New Tank Syndrome. If you want to have a successful home aquarium you need to know a little about your aquarium’s water chemistry and the biological interactions that happen within it. Now don’t get alarmed, none of this is hard, and you may even find it interesting. So let’s get started.

First off, nitrogen. Nitrogen is a gas. About 78% of our atmosphere is nitrogen.. Possibly a boring statistic but think of what that means. We tend to think of the air we breathe as oxygen and carbon dioxide. But really, it’s almost all nitrogen. When the wind blows in our faces, we are being blasted by a wall of nitrogen. When we look out at a sunset, we are staring through a vast sea of nitrogen.

Oxygen on the other hand is 21% of our atmosphere. About one-fifth. The last 1% of our atmosphere is composed mostly of argon. Would you believe carbon dioxide comprises only .03% of our air. That’s three one-hundredths of one percent of our air.

Now we all probably know that carbon is the fundamental element required for life. The next most imortant element is nitrogen. All living organisms, fish, plants, animals, have great quantities of assimilated nitrogen in their tissues. Now when these organisms die or produce waste, they are releasing nitrogen and nitrogenous compounds into the ecosystem.

Now think about your aquarium. Every organism you place in it, whether it be fish, plants, coral, live rock or whatever adds nitrogen based compounds. Food for your fish also adds nitrogen. Excess food, dead plant leaves, fish wastes or any other organic matter will eventually start to putrify and break down. What does this mean exactly? Simply put, bacteria eat the organic wastes and pull out the carbon for their own growth. One of the waste products of their activities is large quantities of ammonia. The bad news is that ammonia in the aquarium is extremely toxic to fish. One way to get rid of the ammonia is to do complete water changes daily - the goldfish bowl technique. The better way is to wait. As ammonia rises in our aquarium, a new set of bacteria will start colonizing the tank. These guys eat ammonia and as ammonia flourishes, so do they. Their population will stabilize at a point where there are just enough of them to continuously keep the ammonai level at 0.

So we buy a water test kit and test the water for ammonia content. At some point it will top out and slowly start to drop. Our ammonia eating colony is growing. But we’re not done yet. These ammonia eaters produce nitrites as a waste. So as the ammonia level drops, the nitrite level rises. More bad news. Nitrites are also toxic to fish.

So ammonia levels drop and nitrite levels rise. If we wait a little longer, more bacteria will grow that eat the nitrites. As this population grows the nitrite level will peak and then drop off, once again until everything is in equilibrium and all the nitrites are gone. Once again we keep testing the water with our water test kit. Once we have 0 ammonia and 0 nitrites, we can start adding fish. Slowly. Too many fish too fast will create more ammonia than the ammonia eaters can consume, upsetting the equilibrium and causing unhealthy or even toxic conditions for your fish.

One last thing. What do the nitrite eaters produce for waste? Nitrates. Nitrates are relatively harmless to your fish unless they build up to very large levels. But they do accumulate and don’t go away. How do we get rid of the nitrates? Periodic water changes. Most aquariums do well with a 10 to 25% water change per week.

So to summarize:

1. Fish waste and organic material in the aquarium produce ammonia - bad.
2. ammonia is broken down into nitrites - still bad.
3. Nitrites are converted to nitrates - good.
4. Excess nitrates are removed through periodic water changes - excellent!

All in all, the whole process from a new tank to a stable cycled aquarium safe for your fish takes anywher from 3 to 6 weeks. There are products out there that can speed up the cycle. But the key to avoiding new tank syndrome is lots of water testing and plenty of patience.

For more in depth information go here, here and here.