1. Choosing the Right Aquarium:
Although it is important to choose an aquarium that you think will look good in your living room, there are other equally important considerations that affect the ongoing expense as well as the health of the inhabitants!
In general we have found that stability of the environment is the most important secret to successful fish keeping. A lot of material has been written about the ideal environment for various species of fish, whether they like warm water or cold water, high Ph or low Ph, hard water or soft water, but this is generally useful only if you are attempting to breed the fish or are planning on keeping a very sensitive fish that is known to be challenging. In choosing all of the items and the fish themselves, always keep in mind the stability of the environment.
2. Size of the Aquarium
Always choose the largest size that fits your living room and your budget!
Don't be fooled into thinking that the smaller the aquarium the easier it will be. Actually, the larger the aquarium is the more stable it will be and the easier it will be to maintain healthy fish. The amount of oxygen available (which is critical to fish survival) is determined mainly by the amount of surface area of the aquarium (not just the size) since oxygen enters the water primarily at the surface. Although aeration, with an air stone or a power head, seems like it is directly adding oxygen to the water, most of the benefit comes from moving water from the bottom of the aquarium to the surface where oxygen is exchanged for carbon dioxide.
Water movement at the surface also increases oxygenation and will generally increase the stocking capacity as well as the health of the fish. Keep in mind that airstones and powerheads can (and generally will) fail at some time or another so don't overstock an aquarium to the point that your fish will die if the power goes out for a couple of hours! It is almost always more desirable to have a few less fish that are colorful and healthy than to push the limits of the tank and risk loosing some of your fish. Not only are fish happier, but the maintenance is easier!
The larger the aquarium, or the fewer the fish, the greater is your chance of having a successful experience!3. Filters and Filtration
There are three main types of filtration for freshwater aquaria: biological, mechanical, and chemical.
Utilizing each of these three types of filtration will provide you with the most stable and most easily maintained aquarium. General aquarium filters manufactured today include each of these three main types of filtration in some manner.
We will also mention several other methods below, that are more commonly used in reef systems, but that can also be beneficial for fish only systems.
The three main types of filtration are:
1. Biological Aquarium Filtration:
This is the most important type of filtration for stability and reduction of toxic wastes. Nitrification: In any biological environment there will be a production of ammonia from normal respiration (fish release ammonia from their gills) and the breakdown of wastes. Ammonia is toxic to fish and in nature is reduced to nitrite by a bacteria called Nitrosonomas. Nitrite is also poisonous to fish and is further broken down into nitrate by bacteria called Nitrobacter. Nitrate is relatively harmless to fish but is a primary food for plants and algae. Frequent water changes (say 10% every week or two) will control nitrate levels. Collectively the process of turning ammonia to nitrate is called nitrification and is carried out in the presence of oxygen (aerobic conditions).
Denitrification: This is the process where nitrates are converted to nitrogen gas in the absence of oxygen (anaerobic conditions). Denitrification is generally not of concern to the freshwater aquarist unless the control of nitrates is desired (See How To Create a Freshwater Aquarium ).
Sponge filters work by passing water over a highly porous sponge where bacteria are allowed to grow. They are almost purely biological with some mechanical filtration provided by the sponge itself. The sponge should not be cleaned or allowed to dry out because this will kill the nitrifying bacteria. Sponge filters are good for breeding situations where very small fish are at risk of being sucked up by the strong intake currents of canister filters or overflows. They are also good for fish like bubble-eyed goldfish that may be injured by strong intake currents of power or canister filters. Sponge filters can be powerd by air pumps or small water pumps. See "How To Create a Freshwater Aquarium"
Undergravel filters are the most common type of biological filter and work by pulling water down through a bed of gravel at the bottom of the aquarium and pulling it up through the uplift tubes. Reverse flow undergravel filters are set up to pull water from the top of the aquarium by pushing it down the uplift tubes and up through the gravel. Reverse flow filters are slightly more efficient since they take water from the top of the aquarium which contains more oxygen.
Since nitrification is more efficient in the presence of oxygen and the air contains about 20% oxygen, as compared to about 7% oxygen for water, trickle or wet/dry filters were developed in the 1980's which increased the efficiency of biological filters dramatically. They place the bacterial growing medium, filter balls with large surface areas, in the air (usually outside the aquarium) and trickle the water to be filtered over them. Many kinds, sizes, and shapes of trickle filters have been in use since they were introduced. Although many trickle filters are external devices used in a sump or hang on the back type of filters, several manufacturers including the "Sea Clear System II" aquarium contain trickle filters built into the back of the aquarium itself. The problem with trickle filters is they usually produce high levels of nitrate, and so are not often used in reef aquariums or other situations where nitrates are undesireable. See "How To Create a Freshwater Aquarium"
Canister filters have a containers or baskets inside the filter for various filter media. For biological filtration you would fill it with some sort of biological media, such as bio balls. This media will either come with the filter or can be purchased separately. Once the bacteria colony has been established on this media you will not need to remove it or clean it.
Standard Power filters use disposable cartridges that have a floss pad surrounding them. This pad is primarily for mechanical filtration but will also house nitrifying bacteria. The drawback to this as a primary biological filter is when you dispose of the cartridge, you dispose of the bacteria colony as well. Today there are more advanced power filters that include a separate area for biological media. These are usually in the form of a compartment in the filter filled with biological media or an attached external 'bio wheel', a pleated wheel that the water flows over as it is leaving the filter and returning to the aquarium. See "How To Create a Freshwater Aquarium"
