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How to Care for Neon Tetra and Cardinal Tetra Fish

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Finatics is a fish enthusiast and enjoys writing detailed guides on how to care for various species of aquarium fish.

How Do You Tell the Difference Between Neon and Cardinal Tetras?

The physical difference between neon and cardinal tetras is that the lower red stripe on the cardinal tetra extends across the full length on their body, whereas with the neon tetra it stops about halfway. In general, cardinal tetras tend to grow a little bigger than neon tetras.

Neon vs. Cardinal

Neon tetras have been in the hobby much longer than cardinal tetras, and they are very intensely bred. Many have been inbred and have become fragile and sensitive. However, cardinal tetras have not been in the hobby as long, and they are more closely related to their wild ancestors; they may not adjust to different water conditions as well. Cardinal tetras are more expensive than neon tetras, as they are the more popular of the two, and many hobbyists prefer the cardinal tetra because of their more vivid coloration.

Care of Neon and Cardinal Tetras

Neon tetras have been in the aquarium hobby longer, and though many have been inbred, the ones that haven't can be robust little critters in an aquarium. They are one of the smallest fish in the hobby and therefore cannot be kept with hungry carnivorous fish. They are active fish that cannot survive well without a school, so they need to be kept in groups of six or more. In the wild, they live in densely planted areas, which means many hiding places should be provided in the home aquarium. It’s recommended to keep neon tetras in slow-running water to mimic their natural environment.

Cardinal tetras are very similar to neon tetras in their care, and they can be kept together in an aquarium. They often even school together! Like neon tetras, they are peaceful, community fish and need to be kept with other schooling fish to feel secure. They originate from the same habitat as neon tetras, so they also should be kept with lots of décor to hide in.

Cardinal Tetras

Scientific Name: Cheirodon axelrodi

Family: Characidae

Distribution: South America, particularly around the Amazon Basin

Temperament: Peaceful, community fish

Diet: Omnivorous, mainly eat insects and larvae

Lifespan: Around 5 years

Adult Size: About 1.5–2”

Tank Size: 10+ gallons as they are active schooling fish

Temperature: 70–78 degrees Fahrenheit

Neon Tetras

Scientific Name: Paracheirodon innesi

Family: Characidae

Distribution: South America, particularly the Amazon Basin

Temperament: Peaceful, community fish

Diet: Carnivorous, mainly eat insects and insect larvae

Lifespan: Can live up to 10 years

Adult Size: About 1.25–2”

Tank Size: 10+ gallons as they are active schooling fish

Temperature: 70–78 degrees Fahrenheit

Natural Habitat

Neon and cardinal tetras originate from the Amazon Basin in South America. They often live in a blackwater environment with lots of tannins in the water coming from decaying wood. In their environment, there is much foliage, from leaf litter to logs to aquatic/semi-aquatic plants. Some neon and cardinal tetras live in clearwater rivers, where the water is clear, but full of vegetation. The water parameters of their natural habitat are soft and acidic, and it’s recommended that this be provided in the home aquarium. They generally live in flowing water, and a good filter (preferably peat-filtered) needs to be used for their tank.

Housing

  • Tank size: As mentioned previously, neon and cardinal tetras are active fish and need plenty of room for hiding places, free room to swim, as well as other members of their school. A minimum of 10 gallons is recommended to keep these fish.
  • Décor: The most natural choices for aquarium décor for neon and cardinal tetras are plants that hail from the Amazon river: for example, the Echinodorus paniculatus, or the Amazon sword plant. Though in the wild there is a lot of decaying wood and leaf litter, this is not recommended in the closed environment of an aquarium, as the breakdown of the matter will cause ammonia levels to skyrocket. As long as there are no sharp edges or poisonous chemicals leaching from it, fake plants and décor work perfectly fine.
  • Substrate: Both species of tetra are fine with any substrate if it is not small enough for them to choke on it. To ensure this doesn’t happen, choose gravel that is too large to fit in their mouth, or choose a substrate with tiny particles, like sand, which won’t really affect the fish if they ingest a bit of it. It’s also recommended to choose a darker colored substrate, as the bright colored substrate can stress fish out. Light-colored substrates also are not a wise choice in terms of aesthetics, because the glowing substrate can make fish appear washed out.
  • Lighting: As the tetras originate from areas with lower lighting, it is recommended to have a dim aquarium light. In order to make the tank even more natural for your tetras, you can grow floating plants that shade the aquarium.
  • Equipment: Neon tetras and cardinal tetras are tropical fish and require a heater that keeps the aquarium at about 72–80 degrees Fahrenheit. In addition, they need a filter to provide a home for beneficial bacteria and to aerate and clean the water. A peat filter is a very natural choice for these little tetras as it creates soft, acidic water and can induce breeding.
Peat-filtered aquariums replicate the natural habitat of neon and cardinal tetras.

Peat-filtered aquariums replicate the natural habitat of neon and cardinal tetras.

Feeding

While the main diet of cardinal and neon tetras consists of insects, they should be fed a variety of other foods as well. This insures that they remain healthy and are eating a balanced amount of nutrients. Make sure to feed only a small amount of food everyday to them, and be sure that everyone in the school is eating. It’s recommended to skip feeding every once in a while, to ensure that they do not become overweight. Here’s a list of foods to feed your miniature tetras:

  • Algae (wafers, live algae, etc.)
  • Bloodworms (frozen, freeze-dried, live)
  • Tropical fish flakes/pellets
  • Baby/small brine shrimp (froze, freeze-dried, live)
  • Wingless fruit flies
  • Tubifex worms (make sure they are cleaned thoroughly before feeding!)
  • Frozen peas that have been de-shelled and thawed (this can help with digestive health)      
  • Guppy/Small fish fry

Tankmates

Neon and cardinal tetras can be the perfect bite-sized meal for many larger fish, so only keep them in a tank with other small, peaceful fish, or herbivorous fish. In addition, they should only be kept with other tropical fish, so goldfish are out of the question. Here’s a list of possible tankmates for neon and cardinal tetras:

  • Bettas (make sure you don’t tank them with an unusually aggressive betta!)
  • Livebearers, such as guppies, platies, etc.
  • White cloud mountain minnows
  • Many other species of schooling tetras, such as lemon tetras
  • Many bottom-dwelling, algae-eating fish (otos, cories, some species of pleco, etc.)
  • Aquatic snails
  • Small, freshwater shrimp such as ghost shrimp
  • African dwarf frogs (don't mistake for African clawed frogs!)
  • And most importantly, more cardinal and neon tetras! They need to be kept with others of the same species, or they will get stressed and could die from complications arising from this.

Research the eating habits of fish that you are thinking about tanking with neon and cardinal tetras before you buy them. Avoid tankmates such as angelfish or Oscars, as they will eat them as soon as they see them.

Good Luck!

Neon and cardinal tetras are very beautiful, small, and rewarding pets, which is why they are so popular in the aquarium hobby. They are not hard to take care of, as long as they are given a good home with a proper diet. Happy fishkeeping!

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Comments

cb on November 21, 2019:

I look at the first photo and I see a neon fish with fin rot. If you notice this, do not buy them or treat the fish with medicines.

Noah on June 15, 2019:

Amazing article! I've been wanting tetras for so long and you helped me decide!

FreshwaterCentral on May 09, 2019:

Thanks for the guide. This article was a great read. I noticed you didn't talk a ton about breeding them, so I wrote up an article for those interested in it (https://freshwatercentral.com/breeding-neon-tetras...

muscleguy32 on March 13, 2019:

Only decaying GREEN leaves will leach nitrates. The leaves used in blackwater aquaria are all brown dried leaves fallen from trees and as such do not leach nitrogen compounds.

My tanks have deep leaf litters and the nitrate levels are negligible. The right leaves can be protective to fish (mulberry, guava, catappa) or can help induce them to breed (banana leaves and gouramis and bettas).

If you keep shrimp the bacterial growth on the leaves will feed the shrimp and some fish will graze on them as well. My female pearl gourami EATS dried phal orchid leaves which grow on trees overhanging the SE Asian streams these fish come from.

I have just added a lot more leaves, the tanks got a bit bare due to economic factors but I have corrected those and got more leaves and my fish are obviously happier, calmer, more active. My ancistrus cat loves being under them, feeling safe so comes out more. My dwarf chain loaches love just swimming and wriggling under them.

Dried leaves will safely rot away to nothing in the tank if not replenished. Many of the fish we keep from soft acid water live in streams filled with dead leaves. So they will feel happy with them in the tank.

eBay is full of people selling pollution free dried leaves. I try and buy the ones which haven't been ironed flat as I think they look more natural.

fish lover on August 18, 2013:

good information as i herd. i herd that you shouldn't keep angelfish with tetras but i like those fish so much!!! arrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrggggggggggggghhhhhhhhhhhhhbut i was wondering if i could keep different types of angelfish with tetras... please let me know as fast as yoou can!!!

jonno96 from Australia on November 23, 2012:

interesting hub and nice pics. Always wondered what the difference was between neons and cardinals!

finatics (author) on June 02, 2012:

@Darren@Essex, yes unfortunately the reason for your struggles might be that the cardinals you are buying are inbred, and yes I prefer sand as well :)

Darren from London on June 02, 2011:

Love tetras, have 24 in my tank, have always struggles with cardinals though, never known why, I think they are even more beautiful than the tetra. I have a 130 ltr tank running with fluval filter, live plants and sand as substrate, although I started with gravel and did the change over, sand is so much better, especially for my corys.

finatics (author) on April 17, 2011:

They are! Especially when they are kept in large schools :) I love watching them interact with each other in their groups. So cute!

Jeannie Marie from Baltimore, MD on April 17, 2011:

I love neon tetras. My mother used to keep quite a number of them in a fish tank when I was a child. They are such beautiful fish.