Neon Tetra Care Guide: Tank Size, Tank Mates, Lifespan and Breeding

Quick answer: Neon tetras (Paracheirodon innesi) are tiny, peaceful schooling fish from the Amazon basin, famous for their glowing blue stripe and red tail. They grow to about 1.5 inches (4 cm), and with good care they can live 5 years or more, though many only reach 2 to 3 because of stress and poor water. Keep a group of at least 10 in a planted tank of 10 gallons or more, ideally 20, at 72 to 76 F with soft water around pH 6.0 to 7.0. What most people get wrong is adding them to a brand new tank. Neons are hardy once settled, but they’re very sensitive to the ammonia swings of an uncycled tank, which is why so many die in the first few weeks.

Neon tetra at a glance

Neon tetra vs cardinal tetra vs green neon vs black neon: which do you have?

The easiest test: look at the red. If it runs only from the middle of the body to the tail, it’s a neon. If it runs the full length of the belly, it’s a cardinal.

Here’s the honest part most neon tetra guides leave out. Neons have a reputation for being “fragile,” but healthy, settled neons are tough little fish. The problem is that they’re mass-farmed, shipped long distances, and often sold stressed. Then they’re dropped into new tanks that haven’t finished cycling. Buy fish that are actively schooling and eating in the shop, add them only to a tank that has been running for at least a month, and acclimate them slowly. Do those three things, and they’re one of the easiest fish you can keep.

How big do neon tetras get?

About 1.2 to 1.5 inches (3 to 4 cm). Females are slightly bigger and rounder than males. They reach adult size within a few months.

How long do neon tetras live?

In a stable tank with good water, neons often live 5 years or more, and some reach 8 to 10. Many only live 2 to 3 years, usually because of shipping stress, an uncycled tank, poor water or disease. A mature tank, soft water and a calm group make the biggest difference.

Neon tetra tank size and setup

Tank size. A 10 gallon tank is the minimum for a small group. A 20 gallon long or bigger lets you keep a proper school of 10 to 15, which looks far better and keeps them calmer. A 55 gallon can hold a stunning school of 25 or more.

Mature, cycled tank. Add neons only to a fully cycled tank, ideally one that has been running for a month or more. See our how to cycle a fish tank guide.

Plants. Neons look brightest and feel safest in a planted tank with dim corners. Easy low light plants like anubias, java moss, crypts and floating plants are ideal.

Substrate and lighting. Dark sand or gravel and low to moderate light make their colors glow. Bright lights over a pale substrate make them fade and hide.

Open swimming space. Keep a clear area in the middle of the tank so the school can move together.

Filter. Gentle to moderate flow. A sponge filter or a hang-on-back filter turned down works well.

Water parameters

Don’t chase a perfect pH. Farm-bred neons adapt to most tap water up to about pH 7.5. Stable water matters far more than an exact number. If you want softer water, add driftwood or Indian almond leaves and change things gradually.

How to acclimate neon tetras

1. Float the bag for 15 to 20 minutes to match the temperature.
2. Pour the fish and water into a clean container and drip in tank water slowly over 30 to 60 minutes.
3. Net the fish into the tank. Don’t add shop water.
4. Keep the lights off for the rest of the day, and feed lightly the next day.

What do neon tetras eat?

• Staple: a good quality micro pellet or crushed flake
• 2 to 3 times a week: frozen or live daphnia, baby brine shrimp, bloodworms or cyclops
• Now and then: spirulina-based foods for variety

Feed once or twice a day, only what they finish in about 2 minutes. Their mouths are tiny, so crush larger flakes.

How many neon tetras should be kept together?

Keep at least 6, and 10 or more if your tank allows. In bigger groups they school tightly, show stronger colors and are much less stressed.

Our aquarium stocking calculator helps you check your full stocking list.

Neon tetra tank mates

Neon tetras and bettas. It often works in a 10 gallon or larger planted tank, since neons are fast and don’t nip. Watch for the first week, and separate them if the betta chases constantly.

Neon tetras and shrimp. Adult shrimp are safe. Neons may eat a few baby shrimp, but in a planted tank with moss, a cherry shrimp colony usually keeps growing.

Male vs female neon tetras

• Females: rounder belly, so the blue stripe looks slightly bent.
• Males: slimmer, with a straight blue stripe.

The difference is easiest to see in adults viewed from the side.

Neon tetra breeding

Neons are harder to breed than most community fish because they need very soft, acidic water.

1. Breeding tank. A small, bare tank with a sponge filter, java moss or a spawning mop, and very dim light.
2. Water. Very soft and acidic, around pH 5.5 to 6.0 and GH under 4, at about 75 F (24 C). RO water and peat or almond leaves help.
3. Condition the pair with live and frozen foods for 1 to 2 weeks.
4. Spawning. The pair scatters small eggs over the plants, usually early in the morning.
5. Remove the adults right after spawning, since they eat the eggs.
6. Keep it dark. The eggs and fry are very sensitive to light. Eggs hatch in about a day, and the fry swim freely a few days later.
7. Feed the fry infusoria or vinegar eels first, then baby brine shrimp.

Neon tetra disease

Neon tetra disease is caused by a microsporidian parasite, Pleistophora hyphessobryconis. Fish usually catch it by eating infected material, such as dead fish, and newly added fish that weren’t quarantined are a common source.

Signs: pale or white patches in the muscle, fading color, a bent or lumpy spine, trouble swimming, and the fish drifting away from the school.

Treatment: there’s no reliable cure. Remove affected fish right away to protect the rest.

Prevention: quarantine new fish for 2 to 4 weeks, remove dead fish quickly, and buy from shops with healthy, active fish. Some bacterial infections look similar (“false neon tetra disease”) and can be treated, so if you’re unsure, ask an aquatic vet.

Common neon tetra problems

Neons dying in the first weeks. Usually an uncycled tank, poor acclimation or stressed shop fish. Test for ammonia and nitrite and fix the water first.

Faded color. Stress, bright light, a pale tank or poor water. Neons also fade at night, which is normal.

Hiding all the time. The group is too small or there aren’t enough plants. Add more neons and more cover.

White spots. Usually ich. Raise the temperature slowly to about 80 F and treat with an ich medication.

Fish disappearing. A larger tank mate, like an angelfish, may be eating them.

Cloudy water after adding fish. A bioload jump. Feed less and test the water. See our cloudy fish tank water guide.

For more easy fish ideas, see our best aquarium fish for beginners guide.

FAQ

How long do neon tetras live?

Often 2 to 3 years in typical tanks, but 5 years or more with stable water and good care. Some live up to 10.

How big do neon tetras get?

About 1.2 to 1.5 inches (3 to 4 cm).

How many neon tetras in a 10 gallon tank?

About 6 to 8, with few other schooling fish. A 20 gallon tank lets you keep a fuller school of 10 to 15.

What do neon tetras eat?

Small pellets or crushed flakes, plus frozen or live daphnia, baby brine shrimp and bloodworms a few times a week.

How many neon tetras should be kept together?

At least 6, and ideally 10 or more, so they school confidently and stay less stressed.

What is the difference between neon and cardinal tetras?

Neons have red only on the back half of the body. Cardinals have red along the whole lower body, grow a little bigger and prefer warmer water.

Can you train a neon tetra?

Not like a dog, but they learn routines. Many neons gather at the front of the tank when you approach at feeding time.

Are neon tetras good for beginners?

Yes, if you add them to a fully cycled, mature tank. Most beginner losses come from adding them to new tanks too soon.