As stewards of creatures from coral reefs and rainforest streams, our first goal is to keep our fishes alive and healthy.

Here are 7 questions to ask before buying a new fish to add to your aquarium:

Scott Michael, aquarium author and former fish store owner, suggests: "Do not be shy about asking these questions at your local fish store. These are exactly the same questions that experts and professional aquarists consider when thinking about acquiring a new fish species."

1. How large does it get? When it reaches adulthood, will it fit into the tank you intend to set up?

2. How aggressive is it? What sort of tankmates might it harm?

3. What does it eat? Does it have specific dietary requirements that will be difficult to meet or does it have a generalized diet?

4. Is it piscivorous (a fish eater) or will it graze on the prize plants or corals you want to keep or devour your prize shrimps, crabs, or snails?

5. What are its habitat preferences? Is it a fish that demands lots of space? Does it have any special aquascaping requirements?

6. Is it susceptible to disease?

7. Is it considered easy or difficult to keep? Do you have the skills (and resources) to be sure it has a chance to thrive?

A Sea of Choices

Walking into an aquarium store with a large livestock section can be mind-boggling if not downright intimidating; there are many hundreds of choices, and new species are appearing all the time. Not only do these fishes display an amazing array of body shapes and color schemes, many may differ in their behaviors, their natural ecology, and their captive requirements.

For example, some of the fishes available to us are highly territorial or so predatory in the wild that they will wreak havoc in a tank full of smaller or milder-mannered species. Pick a species with these instincts and you may see the rest of your fish collection battered or even eaten by the new tankmate.

Then there are fish species so shy that you'll be lucky to see them once they are introduced to a tank full of live rock and myriad hiding places. Choose unwisely and these furtive or passive fish may hide constantly and fade slowly away from starvation and stress.

Feeding is a highlight of the day when keeping an aquarium, but some fishes require two or even three or more meals daily to stay healthy. Others have very specific diets that can be time-consuming, expensive or impossible to provide. Some species need lots of swimming room, while others must have a deep layer of sand to burrow into. Finally, there are also marine fishes available at your local pet store that are destined to grow huge and overwhelm any home aquarium.

To create a balanced, beautiful, interesting aquarium system, the thinking aquarist will need to be aware of the profile and husbandry needs of each fish before making a purchase and adding a new fish to his or her tank.