Penlights that double as lug wrenches, the latest buffalo meat and chocolate cream pie diet book - ever wonder why all these questionable items are grouped together in the checkout lane?

The answer is pretty simple: all of them fall under the heading "impulse purchasing" - things we buy on impulse, without taking the time to consider their usefulness. We are all susceptible. If you don't believe it, look in your garage or "junk drawer."

While most impulse purchases are harmless enough, some are anything but trivial. Consider an addition to the family - of the finned variety. Often, well-intentioned people see a beautiful fish that captures their heart and, without considering the ramifications, impulsively take it home.

The expense of owning a pet is probably the most overlooked consequence of any pet-owner relationship. Advances in pet care, especially in the development of pet foods and medical research, have caused ownership costs to increase over the last 10 years. Since it's not likely that this trend will reverse itself any time soon, potential "pet parents" should consider their finances before taking home a new pet.

While it is certainly not necessary that a fish have a 50-gallon tank to swim in, all owners need to provide the basics of professional medical care, quality food and adequate shelter. The only other necessity for a responsible owner to provide is love - and that's free.

Listed below are approximate costs of basic care for fish. Costs can vary widely, depending on where you live and specifics associated with each individual fish.

Cost of Owning Fish

Most pet owners have - at one time or another - probably tended an aquarium with various guppies, swordtails, mollies, etc. But some aficionados of tropical fish focus on exotic salt-water species. While common species are usually reasonably priced at most pet stores, some rare or exotic fish can cost more than $100 each.

For most average fish owners, the startup costs will be the most significant. The costs of tanks, filters, gravel and decorations will vary considerably depending upon the quality and size of the equipment, the region of the country and individual supply stores. Water quality and environment are also basic necessary provisions.

Annual Costs

Veterinary Care/Medications - $25 to $100
Feeding - $10 to $100
Miscellaneous (tank maintenance, filter supplies, etc) - $50 to $250

Total: $85 to $450

Note: Annual costs do not include the purchase of new pet fish.