To Aerate or Not to Aerate? The beginner aquarist may believe that an aerator, air pump or an air stone is an essential part of the aquarium. While this was a strongly held belief in the past, there are some who no longer abide by this belief. The plants and fish in your aquarium create quite differing reactions to the proportions of gases (oxygen and carbon dioxide) in the aquarium. While plants use carbon dioxide and create oxygen, the fish use oxygen and create carbon dioxide. This also occurs with the plants in the dark. They no longer create oxygen, but carbon dioxide. This puts them in direct competition with the fish for oxygen while the tank is dark!

When fish stand around gasping in a beautiful, plant-filled aquarium, it is not from a lack of oxygen but from an excess of carbon dioxide! Aerators provide the means to remove the carbon dioxide to enhance the gas exchange of carbon dioxide with oxygen. This situation only occurs in aquariums where there is an abundance of plants and tanks that are overstocked with fish.

A well-balanced aquarium can be maintained without aeration, at least during the day. Fertilization with carbon dioxide should only be done during the day, when photosynthesis can be used by the plants to absorb this excess. An aquarium that is lacking sufficient plants or too crowded with fish crowded tanks, the use of an aerator can save the lives of the fish!

However, by using a filtering system that creates an adequate overturn of water, we can again avoid the aerator. In most instances, a filter will be sufficient and preferable to an aerator. Another positive effect of water turnover is that there are no warm areas in your tank. In some aquariums, the surface of the water is several degrees warmer than the water in the bottom due to lighting. This temperature change is not healthy for either the fish or the plants.

Weekends and Vacations with Your Aquarium

Everyone has a well-intentioned friend who will come in and care for your aquarium; however, this can and usually does in a disaster if they are not well versed in caring for your tank. The result is usually too much food rotting on the bottom of your aquarium, the real possibility of dead fish floating around, and a cloudy foul-smelling tank!

Something that few people realize is that in a well established aquarium fish are quite capable of and actually need to fast once a week. Because of this, it is very acceptable to leave the aquarium alone for an occasional weekday feeding or weekend. It is even healthy for them to fast.

Few aquarists would purchase an aquarium if they didn't believe the fish needed them on a daily basis! As a matter of fact, fish are able to survive several weeks without any care from us at all, but you need to follow a few rules for this to be successful!

• For a couple of weeks before you leave do not purchase any new fish or move any fish to separate tanks. This is to avoid fighting and disease that we could not notice insufficient time to fix.

• Don't breed any young fish as they wouldn't survive a long fast.

• Fish can survive an extended fast only in a well-established tank. Don't leave them alone without a well-thought-out plan.

• Do your monthly tank chores two days before you leave. The water change and filter cleaning are especially important.

• Lower the water temperature by a few degrees, as fish have a slower metabolism in cooler water. If it is possible, completely turn off the heater in your absence.

• We may use an automatic feeder but they break down rather easily.

• An automatic timer for lights is a necessity everyday as fish and plants are harmed from too much or not enough light.

As soon as you return check the fish. When they are fed, they won't seem as hungry as before, this is quite normal. The water temperature should slowly be reestablished as soon as possible.

What Causes the Schooling of Fish?

It is fascinating to observe schools of fish as they appear to dance around your aquarium. There are many distinguishing relationships among schooling fish:

• The students of a fish school do not know each other one-on-one.

• There is no limit to the number in the school.

• They seek each other's company; this is called social attraction.

• A school is not attached to a specific part of the aquarium.

You can put several types of schooling fish in one tank, and you should ask your pet store manager which types are compatible to each other. There are several fun tests you can perform with your schooling fish as a means of observing their different reactions.

Divide the fish into species, put each species in a different large glass tubes and put the two tubes on opposite ends of the aquarium. Remove one fish from one of the tubes, and put him in the center of the aquarium. Over a specified time frame, notice how many times he crosses over the center divide of the aquarium. Does he go to the tube with his own species or the other tube?

How do the two species interact with each other when all fish are turned loose in the tank? Do they mix or gravitate towards their own species? Do there appear to be leaders in the different species? How do they react to disturbances in the aquarium and what is their reaction to the addition of a larger single fish into their home? Do they tend to fight, or are they content with their group? Do they prefer a certain area of the aquarium or do they just dance around the entire underwater world.

If there are any problems, they must be addressed immediately. For example, if the other fish seems like he wants to eat your fish, remove it immediately! There are a lot of things you can do to make aquarium observation more enjoyable. Just be sure that you do nothing to endanger your fish and that any changes made can be easily undone.