What Is The Best Freshwater Aquarium Fish Combination? (How To Know)

Are you thinking about setting up a freshwater fish tank?

Do you want to find the right combination of fish for your new tank?

Have you found a lot of confusing and conflicting information out there about freshwater fishkeeping?

If any of this is true of you, then you’ve come to the right place. Below, we’ll walk you through everything you need to know about choosing fish that will work well together in your freshwater tank setup.

But just how important is the compatibility of your fish when choosing the best freshwater aquarium fish combination? It’s very important! Fish that don’t get along will unfortunately fight, injure, and often kill each other—it’s just nature. This is why you should never keep fish together that aren’t good companions for each other.

But there’s more to keep in mind than just that, and there are other factors you’ll want to remember when picking your fish. Check out the information we have listed below for more information and to help you get started.

1. Cold or Warm Water?

Cold Water

  • Cold water fish are not as easy for beginners as warm water fish because it can be challenging to keep the water cool enough for them. Although most people don’t realize this, goldfish are cold water fish and should not be kept in a community tank with tropical or warmer water fish.
best freshwater fish

Warm Water

  • Most good fish for beginner community freshwater tanks are tropical, meaning they’re going to need a heater unless you live in a place where you are sure you can provide a consistently warm water temperature. You’ll need to monitor the temperature of the water for your tropical fish for best results. Do not ever keep goldfish in a warm or tropical water aquarium.

2. Peaceful or Aggressive Fish?


cold water fish
  • When planning a community tank, peaceful fish are an absolute must. You will not have any success with your tank community if you don’t go with peaceful fish. This doesn’t mean you can have some peaceful and some aggressive fish; it means you must have only fish that get along with each other. Even one aggressive fish can wreak havoc on an otherwise peaceful tank in no time, unless you are a very experienced fish keeper and you know how to prevent this from happening.


  • Some of the most beautiful fish in the hobby are also some of the most aggressive. Some may even try to bite you when you clean the tank! Many fish keepers enjoy keeping betta fish, but you have to keep in mind that bettas must only be kept by themselves. You cannot have a community betta tank, even if you keep all females.

3. Large or Small Fish?


  • Bigger fish need more space, plain and simple. Never keep a larger fish in a smaller tank. If you keep a big fish in a small tank, you will not be able to have a community tank at all, since there won’t be enough room for anything else!


  • The smaller the fish, the more you can have in a tank, and the more interesting your tank will look. Little fish like neon tetras are great for community tanks because of this, so make sure you stock up on those that work well in your tank size.
freshwater aquarium fish

4. Male or Female Fish?

freshwater aquarium fish


  • Male fish are usually the best bet for those that are going to be your centerpiece—or, in other words, any type of fish you’re only keeping one of. They are usually more vibrant and nicer to look at than female fish, in most situations. Males should never be kept in groups without females.


  • If you’re keeping a school or a larger group of fish, such as platies or mollies, try to go with females in odd numbers. This establishes a pecking order and keeps the school more peaceful than it would be if you had males and females together—or not enough females.


As you can see, there are a ton of different factors to keep in mind if you’re planning to set up a freshwater community tank. You will need to choose the size of the tank you want, the size of the fish you’ll be working with, the aquarium temperature and water type, and much more. Just remember that, if you’re keeping a community tank, peaceful fish are a must! You should never keep aggressive fish with other types of fish, or you will come home to an unpleasant scene in no time.

Here is a list of some great starter fish for a compatible community aquarium:

colorful freshwater fish for sale
  • Neon tetras. This is the quintessential freshwater community tank fish! They are cute, small enough to keep in a school (which is a must for tetras), and durable enough that they can handle a few beginner mistakes. These are very peaceful little fish that add a lot of color and interest to a tank.
  • Fancy guppies. These go great with neon tetras as well as lots of other types of fish. They require fresh water and tropical temperatures, and they go well in groups of odd numbers—three is the ideal. These fish are livebearers, so keep this in mind if you buy males and females together.
  • Mollies. These fish resemble larger fancy guppies, and they work well in the same conditions as guppies and neon tetra. You can keep a single molly or keep them in groups of odd numbers, like the guppies.
  • Platies. These are ideal fish for community freshwater tanks. They are incredibly peaceful choosing fish that should be kept in groups of odd numbers. They may nip at the fins of long-finned fish like fancy guppies, so keep this in mind!

This is a great setup if you’re looking for suggestions for a starter freshwater community tank. Remember that you can always keep more varied and interesting type of fish later on when you get more experienced, but this is an excellent place to get started.

If you choose to go with saltwater fish, you will need to pick an entirely different tank setup. However, saltwater tanks are much harder for beginners, so they aren’t ideal if you’ve never tried fishkeeping before.

With the right planning, you’ll be able to put together a community tank you’ll want to show off to everyone you know!