What Kind of Fish Do I Put in An Aquarium?

You're diving into all things fishy, and we couldn't be more thrilled. As you dream about building your first aquarium and what type of fish to select, you need to follow a few basic rules for a happy, healthy tank.

How to Select The Right Fish for My Tank 1

Start by browsing the many color options, sizes, and shapes of fish at your favorite pet store to discover which species you find most attractive. Also, take note of which fish live together at the store. This is a good indicator of what you can mix in your aquarium too.

Not All Fish Play Nice Together

Just as the fencing at a dog park keeps big and little dogs from mingling, fish owners also intentionally separate certain types of fish. This helps prevent unnecessary fin nibbling and pushy behavior. After all, we want to gaze into our tanks for relaxation and enjoy the peaceful waterscape, not see a fish fight!

Aquarists tend to keep two common types of fish: community fish and aggressive fish. Let's learn more about each group so you can decide which you want for your tank.

Note: Do not mix community and aggressive species in the same tank. They will fight, often until the weaker species dies.

Choosing Community Fish

Community fish are peaceful pets that accept newcomers to the tank easily, making them a popular choice for new fish keepers. These fish tend to adopt the "live-and-let-live" mantra and aren't prone to fighting or seeing tankmates as prey.

How to Select The Right Fish for My Tank 2

Consider starter community fish like guppies, danios, mollies, tetras, platies, swordtails, barbs, rasboras, otocinclus, and keyhole cichlids.

Choosing Aggressive Fish

Don't be fooled by the term "aggressive." These guys offer tons of enjoyment with quirky personalities, like coming up to the glass each time they see their human approach. And some species "dance" around in the water in anticipation of feeding time.

Fish that fall into this category either defend their territories aggressively or prey on other fish. It's important to do your research before setting up a tank full of these types. In fact, many aggressive fish enthusiasts set up tanks of a single species to reduce the risk of fighting or setting off that prey drive. Keeping an aggressive fish tank isn't easy for those new to keeping aquariums and may be better suited for more experienced aquarists.

A few attractive aggressive species include African rift lake cichlids, Jack Dempseys, puffer fish, and piranha.

A Few More Questions to Ponder

As you consider which type of fish you want to raise, be sure they match the space and type of set-up you envision. Research these questions or ask the pet store for guidance:

  • How big will the fish get when fully grown? Will they fit in the aquarium I have already or plan to buy?
  • What do these types of fish eat? Am I comfortable feeding my pet fish live foods like minnows or mealworms if necessary? (Most predatory fish dine on live food.)
  • Does the species you want to buy thrive with live plants (such as a discus cichlid that loves large broadleaf plants)? Are you interested in raising live aquatic plants?
  • Is this a schooling fish? How many do I need to buy? Is this in my budget? (Some aggressive species carry a high price tag.)
  • If I mix a few species of fish, are their requirements similar (water temperature, feeding, lighting, substrate, etc.)?

Although you may find a specific fish visually attractive, take the time to learn more about them before deciding to add them to your aquarium. The habits, size, feeding preferences, and other requirements of a particular type of fish may just sway your choice! Learn more about fish keeping in the Ultimate Fish Keeping Guide.