When setting up a freshwater aquarium, you want to make sure that you understand which fish will get along. The last thing that you want to do is have your tank proper set up and acclimated, and then a few weeks, or even days, after adding a your initial fish, one or two start to nip and bully the others. This will severely stress out the other fish.
You want to make sure that you keep community fish with community fish, semi-aggressive with semi-aggressive, and aggressive fish with aggressive fish. But, in terms of aggressive and semi-aggressive fish, you want to make sure that you keep similarly sized fish in the tank. With aggressive fish, you want to keep one species per tank, as well.
Check out the following list of fish, so that you can figure out which fish will get along with your current fish, or which fish you want to keep in your freshwater aquarium.
Glowlight and Neon Tetras
- Harlequin Rasbora
- Head & Taillight Tetra
- Horseface Loach
- Leopard Catfish
- Neon Tetra
- Opaline Gourami
- Pearl Gourami
- Penguin Fish
- Rummy Nosed Tetra
- Serpae Tetra
- Siamese Fighting Fish (Betta Fish) **
- Spiketailed Paradisefish
- Spotted Catfish
- Upside Down Catfish
- White Cloud
- X-Ray Fish
- Zebra Danio
Unless marked with a note, the following fish can be housed with other fish on this list without problems or concerns.
- Australian Rainbowfish
- Bala (Tri-Color) Shark
- Banjo Catfish
- Black Neon Tetra
- Black Phantom Tetra
- Black Shark
- Blue Acara
- Blue Danio
- Boesmani Rainbowfish
- Boesman's Rainbowfish
- Bumble Bee Goby
- Cardinal Tetra
- Cherry Barb
- Chinese Algae Eater
- Clown Loach
- Congo Tetra
- Discus *
- Dwarf Gourami
- Dwarf Loach
- Elephant Nose
- Emperor Tetra
- Flame Gourami
- Flame Tetra
- Giant Danio
- Green Catfish
- Glowlight Tetra
* Discus should only be housed with catfish, loaches, neon tetras, and cardinal tetras because discus are very susceptible to disease, require warmer temperatures, and eat slow and will not fight for their food.
** Only house one male Betta in an aquarium, as males will fight till the death. Sometimes two females will be aggressive towards each other, as well. When housing Betta in an aquarium, you want to avoid housing them with other fish who have long fins, such as angelfish and long fin danios. It's best to keep Betta fish with small tropical fish with short fins.
Tiger Barb and Melanistic Tiger Barb
These fish will typically live ok with her fish when they're smaller, but as they age and grow, semi-aggressive fish are prone to nip and chase other fish around. It possible to keep the following list of fish in a community tank, but you want to watch the fish and the tank carefully.
- Bleeding Heart Tetra
- Black Widow
- Buenos Aires Tetra
- Bumble Bee Catfish
- Flying Fox
- Freshwater Puffer
- Green Tiger Barb
- Honey Gourami
- Kissing Gourami
- Red Tailed Shark
- Rosy Barb
- Silver Dollar
- Tiger Barb
- Tinfoil Barb
You do not want to mix the following aggressive fish with any other fist except for fish of similar size of their own kind. IE Red Oscars with Red Oscars and Butterfly Fish with Butterfly Fish.
- Black Paradisefish
- Butterfly Fish
- Green Terror
- Jack Dempsey
- Knife Livebearer
- Red Belly Piranha
- Red Oscar
Samoise on March 08, 2012:
To Happy95... Get yourself a second blue gourami so that they are aggressive toward each other instead of to the smaller ones, I've seen a pearl gourami put a blue in its place for picking on smaller fish. It can all depend on the fish though...
Happy95 on January 26, 2012:
I have a 10gl tank with five guppys and one powder blue gourami and a small catfish that's a bottom feeder. I noticed my gourami has been really chasing my guppys aggressively whenever they are around him. What should I do? Help! :)
Hp on January 22, 2012:
Does pacu fish destroy plants in aquarium?
Jahnda on November 27, 2011:
Some of this imfo is not good. The discus need to grow up with the small fish you plan to have to avoid them eating the little guys. Firemouth need to be in a tank at least 55 gallons. Any fish will eat smaller fish that can fit in their mouth be it on purpose or by mistake during feeding time. If you keep the medium to large tetras, they will nip other fish unless they are in a big shoal of at least 10! The tiny tetras should be bought in a shoal of 6 at a time every week until you have 12-16. "safety in numbers". Molly's are NOT good for most the fish on the list because they require brackish water. Brackish water is between fresh and salt water conditions. If put in fresh water, they will survive, but everyday are dying a slow painful death. They are cool fish and will thrive in a brackish tank! Do your research! Decide on your favorite type of fish, and then build you tank around that fish. Your tank will be a success!!! Research bio-type and compatibles!!! Good luck!
leath james jurca on November 23, 2011:
y dose my water ceep clouding up
Go aggressive fish on January 27, 2011:
I have a red oscar and they are aggressive I think you should add some more aggressive fish to your list like red tailed catfish are not on there and Midis cichlid and about 10000000 more
cat on January 01, 2011:
i have two upsidedown catfish one is a female and a male i think and i think the female is pregnant but im not shere cause she looks like see would be fine but the male has been near her latly and has not left her is she pregnant i would love to take care of her babys i lost my last baby fish to something it was almost an adult it was a guppie
Jon on November 17, 2010:
Blue Acara are evil little chiclids, not community fish, along with (slightly more peaceful, but still predetory) Discus, and Angels. This is HORRIBLE advice.
/It took me a lot of dead fish before I learned what I was doing, but it's worth it.
leslie on October 16, 2010:
Great advice cause we're going to buy some fish.
Whitney (author) from Georgia on August 20, 2010:
carlos on August 19, 2010:
i have two bettas(well i used to) i put my royal red betta fish with two guppies but he ended up killing the two guppies and then dying himself...does anybody have a list of fish that i can put together with bettas?
finatics on August 19, 2010:
Impressive list! Thanks for the nice article, it has some great pictures.
John on July 29, 2010:
Becarful of plecostomos they r peaceful fish but wen they can't find food such as algae or flakes they WILL HARRAS OTHER FISHES TO DEATH AND EAT THEM so BEWARE!
Gus on July 20, 2010:
I have read a lot about aquarium's and my aunt works at New England Aquarium and she and I have been reviewing this page and have found that it has so many inaccuracies.
Even down to basic things like certain fish being categorized as community or aggressive and they aren't.
I hope not too many are paying attention to this page.
Jaimeblair78 from Columbus, Ohio on July 09, 2010:
So, my fiancé and I just got a 10 gal. for my step-son. We have had it all set up for 2 days and we are going to get the fish tomorrow. The woman at the pest store said that we could get these fish that I am going to list as long as me added an 'air stone' so I got a long one and an air pump. These are all of the fishe he wants to put in it: 1 ghost catfish, 3 neon tetras, and 3 zebra danios. Is that too many fish? The woman at the pet store said no since we added more O2 to the tank, but I want to make sure. oh and one more thing, the tank seems to be staying around 74 degrees, I don't have a heater....do I really need one?
1InchTheoryisaMyth on June 14, 2010:
one inch theory only applies some of the time and shouldn't be controlling the number of fish. It depends on the amount of waste that particular fish gives out. User1919, TROPICAL FISH SHOULD HAVE A MINIMUM OF 78 DEGREES FAHRENHEIT WATER TEMPERATURE. I LIVE IN TEXAS YET STILL HAVE A HEATER!!!! so please don't be retarded and get a heater if you plan to continue your fish tank!!
Tamarind on May 30, 2010:
Very thorough hub. I like to use it as a reference when getting new fish to make sure everything is going to work out in the tank. Thanks for sharing all the info:)
Whitney (author) from Georgia on May 12, 2010:
For every 1 inch long that the fish is, there should be 1 gallon. If the fish is 3 inches long or is to be a 3 inch long adult, there should be an available 3 gallons of water for that one fish.
anonymusdolittle123 on May 12, 2010:
I don't get the point of 1 in of fish per gallon. How does this work?
Whitney (author) from Georgia on May 03, 2010:
In a way it really depends on the size of the tank and how many fish you have in the tank. The more fish the more often you will need to change the water.
john on May 01, 2010:
how often to change water
kid on April 19, 2010:
It might be a little too late but for User 1919: Another thing is that for a tropical tank, 75F might be a little to cold for your fish. It's generally 78-82F for tropical fish. Not sure if that will help but it might.
BBBBBBB on April 13, 2010:
me have this huge tank and me don't kno what going on with thee little gapper they seen to be dieing every day and me don't know what to do it a big tank i tell ya
Apollo on March 07, 2010:
my tank is 70 to 100 gallons and there is algae growing on the fake plants and the walls of the tank. i have 60 goldfish so what kind of fish, snails, or anything else that i can put in that will get along with my goldfish.
Fishman on March 04, 2010:
You also need to start leaving some of the algae. You don't have to leave a lot, but some. Many of these fish eat plant matter as part of their regulat diet. You could start using a food that has some plant matter in it as well as algae waffers. You could also use a few live plants like banana plants to give them something soft to nibble on.
Whitney (author) from Georgia on February 22, 2010:
I'd take a guess and say that you're cleaning the tank too frequently.
User1919 on February 19, 2010:
I have a problem, all of my fish are dying and I have no idea what is going on. I think they might be fighting each other but none are aggressive fish. Here is a list:
1-Mickey Mouse Platy
11-Ghost Shrimp (Cleaners)
Casualties So Far-
1-Golden Algae Eater
1-Mickey Mouse Platy
I change about 20% of my water every week and scrub the algae about every time I change the water. The Ghost Shrimp eat any leftover food so I don't worry about overfeeding (I am carefull about that) The tank was established for a few months before I added the fish so the bacteria isn't a problem, I have a filter, Pump, Heater (set to 75 Farenheight) and plenty of decorations that can be used as cover. It is a 30 Gallon Tank, I obeyed the rule of 1 inch of fish per gallon. Anything I missed? I have had fish since I was 5 and have never lost so many fish this quickly.
Freshwater Pro on January 12, 2010:
Interesting...I've never had a semi-aggressive Gourami before, as they (multiple types) have always been timid within the tank's community.
One of the most aggressive fish I've ever owned, are African Cichlids - these boys can fight, and it is not uncommon for them to gang up on individual fish and kill them in no time......and that is in a tank full of of their own species. But, like people, personality varies from one to the next.
Fishman on January 08, 2010:
You should be aware that Angelfish and Discus are peaceful most of the time. But ANY small fish like Tetras or Guppies are fair game and will be eaten at the first chance.
Whitney (author) from Georgia on September 08, 2009:
I'm sorry that it did not work out. On a general basis, discus are a peaceful fish that live well in a community tank.
Other cichlids, on the other hand need to be kept with cichlids alone.
I just looked it up again, and the sources I checked all agreed with discus being peaceful with certain fish, as listed above.
darthvedar on September 06, 2009:
I have had 6 discus and bought 6 little neon tetras thinking that they would bring some variety and fun into my tank.
After 30 minutes or so, my Discus were chasing tetras all around the aquarium, at first I thought they were playing or dunno maybe they were behaving a bit territorial.
But now I have only 5 tetras... :( Appearently Discus are eating tetras. So FYI. Maybe you need to revise this note beautiful.. ;)
hayden on August 14, 2009:
i think this list is very good to help you with your tropical fish tank i have a 4 foot fish tank and i have dwarf gourami simese fiting fish neon tetra sword tail ballon mollys guppies baby eals 2 sucker fishes.
Barbara Bethard from Tucson, Az on June 09, 2009:
wow whitney05 this is a great hub! I agree with bethericksn...I too love the lood of the swordtails and schooling fish...right now am trying out the neons "& platies..and one swordtail....
Whitney (author) from Georgia on May 20, 2009:
Hopefully, you have a large aquarium, but either way when starting an aquarium you should NEVER start off with so many fish at once.
skydiver from UK on May 20, 2009:
Nice hub :) I got my first tropical aquarium on Sunday, bought from ebay. It has 25 (and counting) fish living in it already, but I haven't a clue what they are!! I'm going to make a Hub in the next few days about it, and it would be ace if you could check it out and identify some of my fish for me!!
betherickson from Minnesota on July 28, 2008:
wow nice list and great chart! I personally like the looks of schools of red sword tails.
Whitney (author) from Georgia on July 08, 2008:
funnebone, a chart of men, wouldn't be so bad either. lol
H.C. I've had that problem. Sometimes you can put the semi-aggressive ones in a tank of community without problems, but you really need to make sure that they're the same size. Good luck.
Health Conscious from South Florida - USA on July 08, 2008:
I agree funnebone
Whitney, I've been meaning to get the aquarium going again. Haven't taken the time since last move.
Now I can quit wasting money on fish that eat each other.
funnebone from Philadelphia Pa on July 07, 2008:
I need a chart like that for women.
Great advice, makes me want to go get fish.