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South America


Cardinal tetra

Paracheirodon Axelrodi


    Similar to the more common neon tetra the cardinal has more stunning stripes. More demanding in their water requirements and usually twice as expensive the Cardinal is not a beginners fish. Once established they are relatively hardy and can make a stunning display.

Quick stats:
    Listed tank sizes are the minimum
    Size: Up to 2" (5cm)
    Tank: 20 inches
    Strata: Bottom, middle
    PH: 4.5 to 7.0
    Hardness: Soft dH range: 2.0 - 8.0
    Temperature: 75°F to 84°F (24-29°C)




    Order: Cypriniformes
    Suborder: Characoidei
    Super-Family: Characidoidea
    Family: Characidae
    Genera: Paracheirdon


Common name

    Cardinal Tetra

Image gallery:
    Additional species photographs


    Badmans' Forum


    Northern South America, Venezuela, through Brazil Into Eastern Colombia. Found in the tributaries of the Rio Negro and the Orinoco river.

General Body Form
    This species is more elongated than the Neon Tetra. Which it otherwise resembles in shape. These fish can reach a length of about one and one half inches. Sexually mature females are more stocky than males and are generally a little longer.

    The fins have no color and the upper-side is a Brownish-Red. A wide single stripe extends along each side of the fish from the upper parts of the eye to just below the Adipose fin. This stripe can appear Sea-Green, Yellow-Green or Turquoise-Blue, depending on the angle that the light hits it. Below this stripe is a wide bright Red band that can be seen on the lower half of the body , running from the underside of the mouth including the throat, and all the way back to the base of the Caudal fin. This fish is often confused with the Neon Tetra, but in the Neon the bright Red band is shorter, only running to the middle of the body.

    A somewhat delicate fish that is sensitive to water conditions. The tank should be a planted aquarium, with some floating plants to cut down on the light intensity. A darker substrate material will bring out the Cardinals colors best. Tankmates should consist only of other peaceful species,with no Cichlids. A temperature of 75° to 84° degrees F (24° to 29° c.) should be maintained and water of middle hardness to soft is recommended.


    Found in slow-moving, clear and blackwater creeks with much vegetation

    Soft water, with 1° - 2°of hardness, Ph of 5.0 - 6.0 and a water temperature of about 82° f. Use Java moss or a synthetic substitute over the bottom of the tank and reduce the lighting. Cardinals usually spawn at twilight. The male embraces the female when spawning and about 500 eggs are scattered among the Java moss. Remove the parents. The eggs hatch in about 24 hours and the fry are free-swimming in about five days. Feed the young on Infusoria and later on , newly hatched Brine Shrimp. The Cardinal is not easily bred and most specimens are still imported from their native waters.

Your comments:


Please remember that the following comments are personal experiences and may or may not apply to your setup. Use them as guide to help better understand your fish, like us all individuals will behave differently under different circumstances.


From: Dina
Getting cardinals from a reputable source is key. My local fish store quarantines theirs for two weeks and I've never lost a single one I bought there.
From: Rj
Too many Cardinal Tetra's are killed by good intentions. Very often your wholesaler and fish store have already acclimated their cardinals to their local sub-optimal water conditions for the benefit of their average customer. So when you pop your new fish into warm, super soft acid water you do more harm than good. I've shipped more than a few fish to and from different parts of the country and I often have pretty soft water. Moving fish from soft acid water to harder more alkaline water is much safer than the reverse. Osmotic pressure is important too. I've brought back several shocked floaters from the brink of death by adding salt. If the cardinals are doing well at your local pet shop that shares a water source with your home, don't shock them by giving them optimal water conditions. Move them into a large stress free planted aquarium with aged tap water. Then slowly adjust the water conditions to optimal. It's also nice to wait a week or so after the fish arrive at your local shop before you buy them, let them take the lion's share of the losses. The down side to waiting is that I've seen what bad things can happen to fish at a pet shop in terms of picking up diseases etc. On the up side, after the initial high mortality rate, the cardinals that do survive are usually hardy and long lived. One final point, cardinal tetra's are susceptible to many common and some not so common fish diseases. They should be the last fish you add to a community aquarium after you are sure the tank is healthy. Any disease a new fish brings in is likely to wipe out your cardinals.
From: Jessica H.
These fish are my favorite community fish for more reasons than I have time to type! I got 5 of them about 18 months ago from a fellow fishkeeper. She had already had them for "a really long time". They are so much more hardy than neon tetras, at least in my experience. They look amazing in my planted tank, it's really a sight to see them schooling and they school well with my neon tetras. Their colors truly come out when my PH is between 6.5 and 6.8. Feeding them live tubifex worms a few days a week makes mine very active and very happy. In my opinion, they are the best little community fish out there!
From: Ronald Nichols
One of my favorite aquarium fishes is the brightly colored Cardinal tetra. They tend to be very delicate especially when introducing them to a new tank. Once established they will do well providing that you keep the water very clean ... I found best results by changing the carbon media once a month and doing a partial water change (10%) once a week. The water for the change is first filtered through a solid carbon block drinking filter I purchased from I found that I would lose cardinals especially if they were new by not adjusting the temp of the partial water change first to match the tank water. When I did I didn't lose any. Also hanging a bag of peat in the water greatly helps by keeping the water soft and providing humic and tanic acids which help the cardinals fight disease. Keeping a tank of water outside and allowing mosquito larvae to hatch provide for a special live meal which brings their beautiful colors to a vivid zenith. They benefit greatly from a live diet.
From: Clay
I am no stranger to keeping tetras, however, I purchased 27 of these little guys. The tank is a heavily planted and low light intensity (1.5 watts per gallon) that is suggested along with a Ph of 5.8 in a 46 bow. The only other species kept in the tank was 10 Black Neons. ALL of my Cardinals died with in a week. There seemed to be no stress involved, the Cardinals and Black Neons even schooled together. The odd think is, I never lost a Black Neon out of that tank. I must have picked up a bad batch of Cardinals. But just to make everyone aware...doing exactly what info you find and giving them a nice environment, may just end up being like burning money.
From: K Nicole
The Cardinal Tetra has long been one of my favorite fish for its beauty in schools. However, they are very skittish and not very smart. Also, most specimens are wild-caught during the dry season, so they are already skinny and stressed. I've had rather substantial losses (+50%), even in seemingly healthy fish. I am using a quarantine tank and a three-week cocktail of medications, and the latest batch does seem healthier.

From: Zack
I bought three cardinals to school with my neons. And they were all very healthy and brightly colored. They are or at least I think they are much hardier than neons. A great community fish watch out though because they aren't very big and larger fish might find them tempting.

From: Ralph H.
Cardinal Tetras are just one of my favorite fish. They are more delicate than the neon tetra, though with their brighter more vivid colors they may not appear to be. They prefer a higher water temperature and more acidic water than the normal community tank should have whereas neons do well in community tanks. I found out the hard way that they would make great fishing lures as it seems any fish with a mouth big enough will instantly want to make a snack of them. I recently got a great deal on 50 cardinals and have set up a cardinal only tank (with a couple of cory's as cleaners). It is in an inside room (no sunlight) with black gravel and well planted with Java Fern they make a stunning display. In the two months I have had them I only lost two - and those from the stress of the 3 hour ride home.





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