Cardinal Tetra
Paracheirodon axelrodi
Also known as Red Neon
Edited by Ivan F. · Reviewed
Beginner verdict
Like a neon tetra with the red stripe running the full length of the body, this peaceful schooler glows in a soft, warm, planted tank. It handles warmer water than neons, which makes it a natural partner for rams and other warm-water community fish.
Care at a glance
- Min tank size
- 14 US gal
- Footprint
- 24 x 12 in
- Temperature
- 73–84 °F
- pH
- 3.5–7.5
- Hardness
- 1–12 dGH
- Swim zone
- Mid-Water
- Min group
- 8 or more
- Lifespan
- 4–5 years
Cardinal Tetra tank mates and swim zone
Mid-Water
Spends most of its time in this part of the tank.
Poecilia reticulata
Xiphophorus maculatus
Trichogaster chuna
Trichogaster lalius
Trichopodus leerii
Trichopsis pumila
Barbodes semifasciolatus
Their temperature ranges barely overlap, so you will have little room for error.
Betta splendens
Betta often does best alone. Only try this in a larger, planted tank, and watch closely.
Sewellia lineolata
Their temperature ranges barely overlap, so you will have little room for error.
Ancistrus cirrhosus
Bristlenose Pleco is much larger than Cardinal Tetra and may frighten or even eat it.
Tanichthys albonubes
Their temperature ranges do not overlap, so one of them would always be stressed.
Xiphophorus hellerii
Swordtail is big enough to eat or bully a fish as small as Cardinal Tetra.
Pseudomugil furcatus
One needs much harder water than the other can tolerate.
Compare
Cardinal Tetra feeding and care
How to feed
- Feed micro pellets or crushed flakes small enough for a tiny mouth.
- Add frozen daphnia or baby brine shrimp a few times a week.
- Feed small portions you can see finished within a couple of minutes, because overfeeding fouls the water fast.
Telling males from females
Mature females are noticeably rounder in the body and a little larger than males.
Cardinal Tetra care mistakes to avoid
- Do not buy just one or two. Keep at least 8 fish so they feel secure.
- Do not add them to a brand new tank. Cardinals handle ammonia and nitrite poorly.
- Many are wild caught, so expect a delicate first few weeks and acclimate slowly.
- Avoid fish big enough to eat them, because a small cardinal fits in many larger mouths.
- Check your tank before you buy. Our sourced minimum is 14 US gallons.
Cardinal Tetra tank setup
A forgiving setup with room for a small community.
TankAt least 14 US gal (54 L), 60 x 30 cm
The smallest tank our sources give for Cardinal Tetra. We list only tanks that hold this volume (allowing 10%, so a standard size counts) and have at least this much floor.
Aqueon Standard Glass Aquarium 20 Long US
Aqueon Standard Glass Aquarium 29 Gallon US
Eheim clearTank 73 Spain
Why we chose these (Best 20-Gallon Fish Tank: 20 Long or 29?). Nobody here has used or tested them.
Starter kitA kit with the tank, filter and light in one box
We list only kits whose tank fits Cardinal Tetra, up to twice its minimum volume. A kit whose heater has a fixed setting shows only when that setting is inside Cardinal Tetra's temperature range.
Tetra Complete LED Aquarium Kit 20 Gallon US
Check the heater's setting
Tetra Starter Line LED Aquarium 54 L Spain
Heater preset to 25 °C
Tetra Starter Line LED Aquarium 80 L Spain
Heater preset to 25 °C
Why we chose these (Best Aquarium Starter Kit: What to Look For). Nobody here has used or tested them.
FilterHang-on-back or large sponge filter
Easy to maintain and strong enough for a community without blasting the fish.
Seachem Tidal 55 Power Filter US
Marineland Penguin PRO 175 Power Filter US
Eheim LiBERTY 130 Hang-on Filter Spain
Seachem Tidal 35 Power Filter Spain
Why we chose these (Best Filter for a 20 to 29-Gallon Tank). Nobody here has used or tested them.
HeaterKeep it at 73–84 °F (23–29 °C)
Adjustable heater, about 5 W per gallon: 100 W at 20 gallons, about 150 W at 29. Enough power to hold a stable temperature in most homes. Size up for a cold room.
Aqueon Pro Adjustable Heater 100 W US
Aqueon Submersible Glass Heater 100 W US
Eheim Thermocontrol e 100 Heater Spain
Tetra HT 100 Electronic Heater Spain
Why we chose these (Best Heater for a 20 to 29-Gallon Tank). Nobody here has used or tested them.
Water conditionerDechlorinator such as Seachem Prime
Tap water contains chlorine or chloramine that harms fish.
Seachem Prime US
Fritz Complete Water Conditioner US
API Betta Water Conditioner US
sera aquatan Spain
Tetra AquaSafe Spain
Sold at Kiwoko · Sold at Tiendanimal · Sold at zooplus.es · Maker's details
Why we chose these (Best Water Conditioner for Betta Fish). Nobody here has used or tested them.
Test kitLiquid kit such as API Freshwater Master
Tracks ammonia, nitrite, nitrate and pH while the tank cycles.
API Freshwater Master Test Kit US
API General & Carbonate Hardness Test Kit US
See it at The Shrimp Farm (a retailer; affiliate link) · Sold at Bulk Reef Supply · Maker's details
sera aqua-test box (Cl) Spain
JBL PROAQUATEST COMBISET Plus NH4 Spain
Why we chose these (Best Test Kit for a Freshwater Aquarium). Nobody here has used or tested them.
SubstrateNo special substrate is required; sand with driftwood is suggested for a natural look.
We are still choosing products for this.
Hiding places and decorHeavy planting, driftwood roots and dried leaves are suggested.
We are still choosing products for this.
PlantsSafe with live plants
Cycle the tank before adding animals. See our guide on how to cycle a fish tank.
Where to buy Cardinal Tetra
Stores that list it under the same scientific name as this page. Links marked as affiliate links may earn us a commission. We have not bought from them, so check each store's own terms.
See it at The Shrimp Farm (a retailer; affiliate link)
We have not found a store that sells Cardinal Tetra under its scientific name yet. We add stores as we confirm them.
Live animals and plants travel by courier. Check the store's live-arrival guarantee, and only buy once your tank has cycled (see how to cycle a fish tank).
Some US states restrict certain species. Check our US state aquarium rules table and your state's own rules before you buy.
Cardinal Tetra FAQ
What size tank do Cardinal Tetras need?
Our sourced minimum is 14 US gallons (54 liters), with a footprint of 60 x 30 cm. A bigger tank is always easier to keep stable.
How many Cardinal Tetras should I keep?
Keep at least 8 fish. Bigger groups usually look better and behave more confidently.
What can live with Cardinal Tetras?
Good matches on our list include Fancy Guppy, Platy and Honey Gourami. Avoid White Cloud Mountain Minnow and Endler's Livebearer.
How long do Cardinal Tetras live?
Care guides report about 4–5 years. Stable water and a good diet make the biggest difference.
What is the difference between a cardinal and a neon tetra?
On a cardinal the red stripe runs the whole length of the body, while on a neon it stops halfway. Cardinals also prefer warmer, softer water.
Cardinal Tetra facts and sources
- Family
- Characidae
- Native to
- Upper Orinoco and Negro rivers, South America
- Adult size
- 1.4 in (3.5 cm)
- Temperament
- Peaceful
- Social needs
- Schooling/Shoaling (6+)
- Diet
- Omnivore
- Water flow
- Gentle
- Substrate
- Any
- Live plants
- Yes - Loves Plants
- Shrimp
- Adult Shrimp Only
- Fin nipping
- None
- Vulnerable to nippers
- No
- Breeding
- Difficult in Home Tanks
Sources
- Seriously Fish: Tank size, water ranges and behavior
- FishBase: Cross-check of water ranges and size
Lifespans are approximate and come from aquarium care guides, because these databases rarely publish them.
Where sources differ, we show the Seriously Fish aquarium figures.
Spotted something wrong? Report a parameter correction. For a sick fish, see our veterinary disclaimer.