Setting up your first aquarium can quickly become an expensive lesson in what not to buy—or worse, what you forgot to buy entirely. In this episode, Kenji Takahashi draws on fifteen years of fishkeeping experience to walk you through every piece of equipment you actually need for a successful tank setup, organized by priority and function. Whether you're starting your first twenty-gallon freshwater tank or planning something more ambitious, you'll learn exactly why each item matters and what happens when you skip it or cheap out on the wrong things.

• Your filter should cycle your entire tank volume four to five times per hour, meaning a twenty-gallon tank needs a filter rated for at least eighty to one hundred gallons per hour—and slightly oversizing gives you breathing room as your bioload increases.

• The two to t ...