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How to Buy Freshwater Aquarium Fish (With Community Tank Ideas)

Having worked with fish most of my life, I have a strong desire to help others to be successful in the hobby.

Three Spot Gourami

Three Spot Gourami

Buying Fish for Aquarium

Spotting that perfect fish and bringing it home without any preparation makes it likely that the fish won't live through the experience. It is important that you only purchase one or two fish at first, depending on the size, before adding more fish. This will help the nitrogen cycle start to develop in your tank.

After a couple of weeks, you can then add another fish and wait for the aquarium to adjust before adding more fish. Never add more than a couple of fish at a time. This can disrupt the nitrogen cycle, creating a deadly environment for your fish.

Guideline: 1 Inch of Fish per 1 Gallon of Water

As a general rule, you should be able to keep 1 inch of fish for every gallon of water if it is properly filtered and aerated. Don't forget to take into consideration the ultimate size your fish will grow to as it matures.

Your fish tank should already have been set up for at least 24 hours (much longer for saltwater) and should have been properly prepared for the type of fish you intend to purchase.

Supply List

Great starter kits can be found at your local pet supply store. These kits are usually much less expensive than buying the individual parts separately.

At a minimum, you will need the following equipment before purchasing your fish:

  • Tank
  • Hood and Light
  • Heater
  • Filter
  • Gravel
  • Fish Food
  • Decorations and Plants
  • Net
Example of a basic aquarium starter kit

Example of a basic aquarium starter kit

Tips on Selecting Fish

Consider the health of the fish you want to buy, as well as whether they get along with all of the species you want in your tank.

Buy Good, Healthy Fish

Buy only good, strong, healthy fish for your aquarium. Introducing weak or injured fish to your tank can also introduce deadly diseases killing everything in the tank.

Watch for any signs of disease in the tank where you purchase your fish. Any signs of dead fish, white spots (ick), torn fins, or patches that look like cotton are all signs of disease that you could be taking home to your own tank.

Check the Compatibility of Aquarium Fish

To ensure the health and well-being of your freshwater tropical fish, it is important that you select species that are compatible with each other. Many varieties such as the African Cichlid are known for their aggressiveness and will not get along with other types of fish.

How to Create a Community Tank

One of the best ways to ensure the compatibility of the fish in your aquarium is to create a community tank. Community tanks are collections of fish that are known to get along and have similar environmental and dietary needs.

The following are some examples of different types of community tanks you may wish to try.

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Read More From Pethelpful


One of the easiest community fish tanks you can have is a goldfish community tank. Goldfish can grow to considerable sizes so be sure to take this into consideration when creating a goldfish community tank.

Goldfish should only be kept with other Goldfish or Koi. While you may be able to find fish that can handle the cold water environment that Goldfish enjoy, Goldfish have different dietary needs and rapidly outgrow other tank mates.


Guppies come in a wide variety of colors and have been bred to produce several different types of exotic fin shapes. Breeding guppies are very easy producing a brood every four to six weeks. Each brood may have several dozen baby fish or fry. Guppies enjoy eating decaying pieces of aquatic plants so live plants provide an important part of the guppy diet.


A livebearer aquarium can be one of the easiest tanks to set up. Livebearers are usually quite hardy and come in a wide variety of colors.

Your livebearer fish are bred very easily. If you do choose to try to breed your livebearer fish be sure to provide plenty of hiding places for the fry so they don't get eaten and move them to a different tank as soon a possible.

Male (top) and female (bottom) Mollies

Male (top) and female (bottom) Mollies


Mollies are very easy to take care of and will do well in a community aquarium with Livebearer fish. Although mollies can live their entire lives with other Livebearer fish, they do best if kept in brackish water.

The additional salt in brackish water helps them maintain a healthier slime coating and lowers stress levels.


Platies are very easy to take care of and comes in a wide variety of colors. There are even been some unique shaped Platies. Platies, like Molies and Guppies, are very easy to breed.

Under certain circumstances, female Swordtail can change into a fully functioning male.

Under certain circumstances, female Swordtail can change into a fully functioning male.


Swordtails can provide additional interest for your aquarium. Most Swordtails are quite peaceful however they may be aggressive at times. Be sure to have a good lid on your aquarium to prevent them from jumping out.

Male Swordtails have a sword and the females generally don't. In an aquarium of only female Swordtails, a female Swordtail can actually turn into a fully functional male. Often older female Swordtails will grow a gonopodium (male productive organ) and a sword on their tail.

Bleeding Heart Tetra

Bleeding Heart Tetra

Danios and Tetras

Danios and Tetras are schooling fish and should have at least three of each species in the aquarium. Both Danios and Tetras are very easy to take care of and usually provide lots of activity for your aquarium.

If given the proper environmental conditions and diet, some Tetras and Danios are fairly easy to breed. Danios and Tetras are egg layers.


These cute little guys in the image above can grow to huge sizes. Be prepared to have a huge tank for these hungry Oscars.

African Cichlids

If you don't want the cost of a saltwater tank but like the bright colors of saltwater fish, African Cichlids may be the perfect choice for you.

These fish are known for their aggressiveness and won't get along with any other types of fish. They are also known to destroy just about anything in their tank so live plants are not a good choice in African Cichlid tanks.

Jack Dempseys

Named after the 1920s heavy-weight boxer for its love of beating up other tank mates, this South American Cichlid is quite aggressive and is best kept with fish that are similar in size and temperament.

Jack Dempseys are beautifully colored and can grow to over 12 inches long, so they require lots of swimming room. Jack Dempseys become much more aggressive if kept in cramped quarters. Provide them with lots of hiding places and don't be surprised if it rearranges the tank décor from time to time.

If you happen to get a pair, you have a good chance of breading the Jack Dempsey if they are given the proper environmental and dietary considerations.

The Boesemani Rainbow is an active schooling fish.

The Boesemani Rainbow is an active schooling fish.

Mixed Fish Variety Community Tanks

To have a more interesting aquarium, you may wish to mix different species of fish together. Special care must be taken to make sure that all of your fish will get along and that they all have similar dietary and environmental needs.

You should also keep in mind the zone that the fish usually inhabits. Does it like to swim at the top, bottom or in the middle of the aquarium? An ideal aquarium will have all three zones occupied.

Here is an example of some of the fish that you could add to the same tank to get a nice community aquarium if desired:

  • Most Barbs
  • Cory Cat
  • Most Danios
  • Loaches
  • Sharks
  • Swordtails
  • Tetras
  • Rainbow Fish
  • Plecostomus
  • Platies
  • Mollies
  • Most Gouramis

Remember: Learn About Your Fish Before You Buy

In any case, learn about the fish you intend to buy before you purchase it. Fish like the Kissing Gourami above look friendly enough in the pet shop but can raise havoc in your tank if placed with the wrong tank mates.

Other Fish and Creatures to Add to Your Aquarium

You may be interested in adding some bottom feeders or other aquatic creatures to your tank, like shrimp. There are special considerations to keep in mind for these fish as well.

Fish That Provide Special Services

Some fish help to keep your aquarium free from algae and excess food such as the Plecostomus and Chinese Algae Eater.

  • Chinese Algae Eater: Use caution when purchasing a Chinese Algae Eater, aka Sucker Fish, as they can get quite aggressive as they get older. The name Chinese Algae Eater is kind of a misnomer because they don't do that much to clean algae from the tank. They are best for cleaning excess food from the bottom of the tank.
  • Plecostomus: These fish are great at getting rid of algae; however, they grow rapidly and can soon become unmanageable in a small aquarium.
  • Cory Cat: This fish does a great job of cleaning the bottom of the tank and will get along with most peaceful fish. The Cory Cat makes a great addition to a peaceful community aquarium.

Crabs, Frogs, and Shrimp, Oh My!

You may be tempted to get a specialty creature for your aquarium such as a crab, frog or shrimp. Most of these creatures do best in a tank with its own kind.

  • Fiddler Crab: In the case of the Fiddler Crab, it will eat just about anything, including any fish you try to put in with it.
  • Ghost Shrimp: These make good additions to a tank with very small peaceful fish.
Freshwater Aquatic Plants

Freshwater Aquatic Plants

Live or Plastic Aquarium Plants?

Plants not only add to the beauty of an aquarium but also gives the fish a place to hide. Some fish like Goldfish will benefit from eating some of the plants you place in your tank. It is important to know if your fish will be peaceful not only to other fish but also to any plants that you may add to your aquarium.

Some species of fish, like Cichlids, will tear up your plants soon after you place them in the tank. Plastic plants may be a better option in cases where your fish will destroy them too quickly.

A great looking saltwater aquarium with Blue Green Chromis.  Blue Green Chromis is an excellent saltwater fish for a beginner.

A great looking saltwater aquarium with Blue Green Chromis. Blue Green Chromis is an excellent saltwater fish for a beginner.

What About Saltwater Tanks?

A great-looking saltwater aquarium is a wonder to behold. As with freshwater aquariums, saltwater tanks require that suitable tank mates be found. This goes not only for the fish but also the other creatures that frequently inhabit a saltwater aquarium.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: Is it an obligation to have live plants for guppies?

Answer: No, not at all. However plants help create stable water conditions and usually help fish feel more safe. Aquariums without live plants usually need to have more frequent partial water changes.

Question: are goldfish and tetras compatible?

Answer: I would not recommend housing them in the same aquarium.

Many tetras tend to nip fins on slower moving fish.

Another reason there would tend to be issues is that goldfish grow at a much faster rate and much larger than most tetras.

If the tetras were a less aggressive type, the goldfish would likely start picking on the tetras as the size differences increases.

© 2013 Marty Andersen


FrodogenicFrogs on August 18, 2019:

TY for the info:) I introduced my children to community aquariums with swordtails, guppies and small catfish and they were a joy to raise& better than watching tv most evenings! I’ve learned that live plants of different heights are good for breeding and hiding plus overall tank health—and should be looked over carefully if you are unfamiliar with the seller or segregated in a separate tank for 3-5 days prior to introduction into the main tank, that way if the seller has used the tank & plants to for other species eg. sea snails, & the larvae come out all at once you won’t spend days clearing the glass and substrate!

prasetio30 from malang-indonesia on January 27, 2013:

Very inspiring hub. I love fish and all your tips here. Including all beautiful pictures and the video as well. Thanks for writing and share with us. Voted up!


Weekend Hobbyist on January 26, 2013:

Hey Knight,

Lol at Congress but think about it, all throughout history there have been people who do that but everything is exactly the same so not a feasible solution.

However here's a link to details about assassin snails if you want to use some in your planted tank:

They have a nice design on their shell so aesthetically they are still a sight to see. Enjoy! - Btw if you're keeping shrimps like red cherrys they are ok to use too. In my experience PH and Nitrates are a bigger killer than these slow little guys.

Knightheart from MIssouri, USA on January 26, 2013:

Hey Weekend,

Never heard of assassin snails...sounds like we could use some of those in Congress! The problem politicians would be gone and the others as well, leaving the country in the hands of the people where it should be! LOL

Weekend Hobbyist on January 25, 2013:

I had a problem with keeping snails in my planted tank and the eggs do look terrible. I followed a suggestion of a friend and used assassin snails - well lets just say I had no problem with snails anymore. Rather I had no problem with snails entirely because the assassin snails wiped out the snail population and disappeared as well.

Abbyfitz from Florida on January 25, 2013:

Great hub! I'm not an aquarium owner (I'm lazy lol) but I love to watch all the colorful fish. You gave clear instructions that a novice like me could have a great tank in no time!

Marty Andersen (author) from Salina, Utah on January 25, 2013:

Your absolutely right Plecostomus do get HUGE! For community tanks I prefer Cory Cats.

I forgot to mention snails, I'll have to edit the Hub to cover snails because they do become a big problem due to the number of eggs they lay.

Good job on getting your Angel Fish to breed! I was fortunately enough to have some Paradise Fish breed. They build a bubble nest like Betas do.

Thanks for the comment, I'm definitely going to add information on snails.

Knightheart from MIssouri, USA on January 25, 2013:

Nice and informative hub. I have had aquariums for many years, mostly community fresh water. I used to have great luck with marble angel fish..actually getting them to lay eggs and breed. But, I have to make a warning about have a plecostomus. Usually they are very small when you get them but the can grow to huge sizes. I had one in my 29 gallon and it when startled, like a light coming on, it went nuts. It broke several submerged heaters and snapped the plastic tubes to my Mag 300 canister filter and outside Whisper Filter. I had to get rid of it since it did so much damage. Glow fish are really nice have and always had a special fondness for cardinal and neon tetras. Oh, another caution is to not use snails. They breed like mad and your glass seems to be covered with eggs all the time. Great hub and SUPER photos of the fish!

RTalloni on January 25, 2013:

An interesting look at what fish to purchase for an aquarium that people will find helpful. Congrats on your Hub of the Day award for a well-done hub!

Comfort Babatola from Bonaire, GA, USA on January 25, 2013:

This is a very useful hub. Very well written too. I learned a lot more about fish/aquarium than I ever knew.

Voted up and useful. Will share

Marty Andersen (author) from Salina, Utah on January 25, 2013:

It's interesting you should mention that. Many years ago we had a pet hamster that we kept in a ten gallon tank.

We had identical twin boys that were very curious so we had to keep the tank up high where they couldn't get to it.

If I recall they were 5 or 6 at the time.

One day they decided they would get a chair and stack other things on it so they could get to the tank. As they tried to get the tank down, one of the twins dropped the tank on the head of the other.

The result was 99 stitches and a nearly sliced off ear.

Fortunately we were able to get good medical attention and there are no signs of any scars at this point.

A fish tank can be dangerous if use for a cage or an aquarium. It didn't finish us with aquariums or using tanks for our pet rodents however we don't keep them up high anymore.

Liz Elias from Oakley, CA on January 25, 2013:

When my kids were in school, we tried an aquarium. We had it set up in advance, got the full-on kit--under-gravel filter, light, hood, etc...

It was a disaster from the get-go. The algae-eaters did not do their job, and I was constantly scraping the sides so we could see in; the filter system did not work well, and I had to do the old-fashioned kind in the end, and manually empty and clean the tank from time to time.

The end came when my then-8-year-old daughter decided she was going to "help" and feed the, she pulled out the drawers in the chest the tank was sitting on, to use as a ladder...with 10 gallons of water, the gravel, the aquarium itself, and her added weight on the front of the dresser--over it all went! CRASH! No more fish; ruined wool rug; gravel everywhere, and permanent water stain on the hardwood floor under the rug.

Congratulations on Hub of the Day--this was a very well done article with great photos and clear explanations. (However, that experience finished me on aquaria. I'll stick with my cats from here on out.) ;-)

Voted up, interesting and useful.

Ann-Christin from UK on January 25, 2013:

This is a really nice and informative hub for beginners. I started out with 3 Platy fish just over a year ago I now have over 20 they are definitely easy to breed.

Weekend Hobbyist on January 25, 2013:

Great hub! I have an african cichlid tank myself. I made the mistake of adding a blue lobster in the tank. I just realized how aggressive these fish can be. I have a nice rock wall so I thought the lobster would be able to hide from them but I was wrong. "Know your fish" before buying! I enjoyed reading - keep up the hobby! Thanks!

Emma Kisby from Berkshire, UK on January 25, 2013:

Very useful hub. I had goldfish in the past but found they polluted the tank very quickly, meaning cleaning it out all the time.

We were recently given a tank and were advised to get aquarium fish which could live in cooler temperatures and were easy to maintain. We also had to get the tank set up with the right PH level for our area - which was easy but I didn't know! We now have a selection of danios (put in first to establish their new environment) and rosy barbs - as well as 2 sucking loaches to clean the tank!

Your article is full of really useful information and I've learned a lot about keeping fish. Thanks!

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