Freshwater fish care and tank mates, with the reasons
Which fish can live together, how many fit your tank, and how to keep them healthy. Every fact is quoted from published care guides.
Start here
Best fish for beginners →Starter sets, how many to buy and what they cost.
Best fish for my tank sizeWhat fits, how many, and what outgrows it.5 gallons10 gallons20 gallons
Setting up a new tank →Let the filter grow good bacteria before any fish go in. It takes weeks, and it’s the step most beginners skip.Tank mates for my fish →Yes, maybe or no, with the reasons, for every species we cover.Most-asked tank mate questions
- Can a betta live with guppies? Maybe, 20+ gal
- Can a guppy live with platies? Yes, 20+ gal
- Can a guppy live with fancy goldfish? No
- Can two bettas live together? No
- Can an ember tetra live with neon tetras? Yes, 10+ gal
- Can an angelfish live with guppies? Maybe, 30+ gal
- Can a betta live with pygmy corydoras? Yes, 10+ gal
- Can a fancy goldfish live with cherry shrimp? No
Stocking calculator
Add your tank size and fish. It shows how full the tank would be and checks water, temperament, fins and group sizes.
Check my fishFish by type
Schooling fishSmall fish that feel safe only in a group of their own kind; they fill the middle of the tank.Ember tetra · Neon tetra · Tiger barb (nips fins)
LivebearersHardy, colorful fish that give birth to live young, so expect babies if you keep males and females.Guppy · Platy
Bottom dwellersThey live and feed on the bottom; most need a group and soft sand.Bronze corydoras · Panda corydoras · Pygmy corydoras
Centerpiece fishOne or a few larger or showier fish that the rest of the tank is planned around.Angelfish · Betta fish
Coldwater fishThey need cool water, so they can't share a tank with tropical fish.Common goldfish · Fancy goldfish
Shrimp and snailsNot fish: optional clean-up crew that grazes algae and leftovers.Cherry shrimp · Zebra nerite snail
How we check a fact
Guppy water temperature: we use 72–82°F (22–28°C), ideal 76–78°F. 4 care guides, each quoted:
- seriouslyfish.com “17–28°C 63–82°F” 63–82°F
- aquariumcoop.com “An aquarium heater is recommended to keep the water warmer at 76 to 78°F” 76–78°F
- practicalfishkeeping.co.uk “Temperature: 22-28°C (72-83°F).” 72–83°F
- fishlore.com “Temperature : 66°F - 84°F (19°C - 29°C)” 66–84°F
Why 72–82°F: Aquarium Co-op's 76–78°F is the ideal; Practical Fishkeeping's 72–83°F is the tolerated range, which is what matters for tank mates.
Free, no ads, no signup. Our research is AI-assisted, and every fact is quoted from published care guides (how we check). Spotted a mistake? corrections@fishtankatlas.com