Whether you’re a beginner or have been raising pet fish for a few years, you’re bound to eventually encounter a major problem. How on earth do you keep those wonderful fish alive in your tank for any length of time?

Sometimes the loveliest of the lovely or the rarest of the rare is the hardest of all to maintain. If you’re having trouble keeping these aquatic pets, you need to purchase one or more of the best types of low-maintenance fish.

According to Hartz, the best bet for a new fish owner is starting with a community tank. All the fish in it should be low-maintenance types. Hartz recommends that you begin with robust species that won’t drain your checking account. On the list are swordtails, mollies, platies, zebra danios, and coryadoras catfish. All of them have been bred in various colors. They’re all easy to care for as well as affordable.

As you gain experience with pet fish, you might decide to move on to more expensive fish that are a little more difficult to keep. Whether you do so or stay with easy-maintenance types, you’ll need to be careful not to add too many fish to the tank as you grow the community.

Pet Care Education suggests that five types of fish are the easiest in terms of maintenance:

Upside-Down Catfish. Its scientific name is synodontis nigriventris. This fish apparently has the charming habit of swimming mostly while it’s upside down. It’s a small African fish known to be hardy in various water conditions. These fish love living in trios. They do well if you feed them a combination of flaked, frozen and live food.

Goldfish. Ever-popular with children as well as adults, these orange fish can actually be purchased in a number of colors due to genetic variations. You’ll want to feed them only goldfish food, which is relatively inexpensive and sold in most pet stores.

Danio. You’ll quickly notice that these fish love to eat. They’re low maintenance as far as being able to happily digest most fish food. As a matter of fact, if you mix types of fish in your tank, you might see a danio try to steal food from the other types. These fish are just filled with energy and dart endlessly across their aquarium. They need a tank with sufficient swimming space to prevent them from becoming a bit aggressive.

Betta. These days, you can find them in groceries and even big-box stores that sell home decorations, not just in pet stores. They’ve become popular because they’re so colorful and hardy. They thrive in various temperatures, pH levels and other water conditions.

Rosy Barb. Although they can reach six inches long, these East Indian fish are related to minnows. They’re also native to other parts of Asia. They range from pink fins on females to red for males. Peace-loving fish, they thrive in communities of five or more Rosy Barbs. This keeps any one fish from becoming overly feisty.

The average lifespan varies greatly from one type of pet fish to another. Before deciding on the ones you want to buy, be sure to do a little research to how long you can realistically expect them to live.