If raucous barking, early morning walks, or daily litter box cleanup aren't your thing, consider adopting a tank full of nearly self-sufficient and serene companions.

Lionfish never roar - and you'll hardly hear a peep from piranhas - as they glide through their aquatic world. Apartment dwellers especially enjoy these quiet pets, who won't wake neighbors or stain the landlord's shag carpet.

Studies show that fish have a calming effect on most people and can even help lower blood pressure. The aquarium's soothing hum and gurgle calls to mind a bubbling brook, while its finned inhabitants circle plants with mesmerizing grace.

With some 500 species of tropical fish available, you have an abundant choice of colorful companions. Consider flashy blue and red bettas, exotic goldfish with bulbous orange foreheads, transparent glass catfish, or dazzlingly striped zebra danios.

Visit your local PETCO and aquarium clubs to see which species catch your eye. But do your homework before you buy to make sure your finned friends share habitat and water-quality preferences - your fish will be healthier and you'll experience fewer maintenance headaches.

The best part about owning fish is you can tailor your tank to your interests. A simple 10-gallon aquarium with a basic undergravel filter, heater, air pump, rock, and plastic plants suits some fish keepers just fine. Others enjoy creating an elaborate aquatic ecosystem where vibrant fish and plants flourish.

Feeling intimidated by the supply list? Start with one fish to see if the two of you are compatible. You don't need to break your budget - just fulfill your pet's basic needs. Then kick back, relax, and enjoy your fascinating new friend.