If you think fish are the perfect starter pets, think again. They rely on us for all their environmental needs, and that’s a daunting responsibility. So, let’s look at what you should do even before you bring any fish home.

First, you’ll need to research which species of fish can live together. After all, different species need different microclimates. As you set up their tank, you’ll need to factor in the right temperature, water pH — that’s the degree of acidity and alkalinity — as well as light.

It’s crucial to set up a balanced bacterial population before bringing any fish home, and that takes at least two to four weeks. Establishing that so-called biofiltration is key to controlling toxic waste levels that can be lethal to fish.