The neon tetra is one of the most recognisable fish in the hobby, and for good reason. A shoal of them moving through a planted tank, blue stripes catching the light, is hard to beat. They are small, peaceful and inexpensive, but they are not quite as bulletproof as their reputation suggests. Get the basics right and they will live for five years or more. This guide covers everything you need: tank size, water, diet, tank mates, health and breeding.
Neon Tetra at a Glance
| Scientific name | Paracheirodon innesi |
| Adult size | 3 to 4 cm |
| Lifespan | 5 years or more with good care |
| Minimum tank | 54 litres (60 cm long) |
| Temperature | 20 to 26°C, ideally 22 to 25°C |
| pH | 6.0 to 7.5 |
| Group size | At least 6, ideally 10 or more |
| Temperament | Peaceful, shoaling |
| Diet | Omnivore |
Where Neon Tetras Come From
Wild neon tetras live in the slow, tea-coloured blackwater streams of the upper Amazon basin in Peru, Colombia and Brazil. The water there is very soft, acidic and shaded by forest, with a bed of leaf litter and roots. Almost every neon sold in the UK today is farm-bred, mainly in Asia and Eastern Europe, and these fish are far more tolerant of ordinary tap water than their wild ancestors. Even so, they still look and behave their best in conditions that lean towards the soft, dimly lit water they evolved in.
Neon Tetra vs Cardinal Tetra
The two are often confused. On a neon tetra, the red band runs only along the rear half of the body, from roughly the middle to the tail. On a cardinal tetra, the red runs the full length of the belly from nose to tail. Cardinals are also slightly larger and prefer warmer water, around 24 to 28°C, which makes them a better fit for tanks kept with discus or rams. If you are weighing the two up, our cardinal tetra care guide covers that species in the same detail.
Tank Size and Setup
Neons are small, but they are active swimmers that need horizontal space to shoal. A tank of at least 54 litres and 60 cm long suits a group of 8 to 10. Bigger is better: in a 100 litre tank or larger, a shoal of 15 to 20 will school tightly and show far more natural behaviour.
The best setup mimics their home waters:
- Dark substrate. Sand or fine gravel in a dark colour makes their colours far more vivid. Pale substrate tends to wash them out.
- Plenty of plants. Live plants give cover and help keep water quality stable. Leave open swimming space along the front and middle.
- Subdued lighting. Floating plants or a lower light setting reduce stress. Neons under harsh light often hide and fade.
- Gentle flow. A filter sized for the tank, with the outflow spread or baffled, so they are not fighting a current.
- Botanicals. Driftwood and dried leaves release tannins that soften the water slightly and tint it amber, which neons love.
Water Parameters
Farm-bred neons will adapt to a wide range, but stability matters far more than chasing exact numbers. Aim for:
- Temperature: 22 to 25°C. They can tolerate cooler, down to about 20°C, but they are more active and live longer in the middle of the range. Avoid keeping them permanently above 26°C, as warm water shortens their lifespan.
- pH: 6.0 to 7.5. Most UK tap water sits within or close to this.
- Hardness: Soft to moderately hard. Very hard water is tolerated but rarely ideal.
- Ammonia and nitrite: Always zero.
- Nitrate: Below 20 ppm, kept down with regular partial water changes of 20 to 30 percent each week.
Never add neons to a brand-new tank. They are sensitive to the ammonia and nitrite spikes of an uncycled aquarium, and this is the single most common reason people lose them in the first fortnight. Wait until the tank is fully cycled and stable, ideally a couple of months old, before adding them.
Shoal Size and Behaviour
Neon tetras are a shoaling species, and numbers are not optional. Kept in twos or threes, they become stressed, pale and prone to disease. A group of at least six is the absolute minimum; ten or more is where they really settle and start moving as one. In a larger shoal you will see them spread out through the tank to feed during the day and then pull together into a tight group when something startles them.
They spend most of their time in the middle of the water column, which makes them a natural partner for bottom dwellers and surface fish.
Best Tank Mates for Neon Tetras
Neons are completely peaceful, so the main rule is simple: avoid anything big enough to eat them or boisterous enough to bully them. Good companions include:
- Corydoras catfish, such as panda or pygmy corydoras
- Other small tetras, such as embers and rummy noses
- Small rasboras, such as harlequins and chili rasboras
- Dwarf gouramis and honey gouramis
- Otocinclus and small bristlenose plecos
- Peaceful livebearers such as platies and endlers
- Nerite snails and adult shrimp
Avoid angelfish once they are fully grown (a large angel will happily eat neons), most barbs that fin nip, and any fish with a mouth big enough to swallow a 3 cm tetra. For a fuller list of compatible species, see our guide to the best tetra tank mates.
What to Feed Neon Tetras
Neons are omnivores with small mouths. In the wild they pick at tiny insects, larvae, crustaceans and plant matter. In the aquarium, a varied diet keeps their colours strong and their immune system healthy:
- Staple: a good quality micro pellet or fine flake, crushed if needed.
- Frozen foods: brine shrimp, daphnia and cyclops two or three times a week. Bloodworm is a treat; chop it finely and offer it occasionally.
- Live foods: baby brine shrimp or daphnia, if you have access, are excellent for conditioning.
Feed small amounts once or twice a day, only as much as they will finish in about two minutes. Overfeeding is a far bigger risk than underfeeding, as leftovers quickly foul the water. You will find suitable staples in our aquarium fish food range.
Common Health Problems
Neon tetra disease
Caused by a microsporidian parasite (Pleistophora hyphessobryconis), this shows as patches of fading colour, usually starting near the blue stripe, followed by a lumpy or curved spine and erratic swimming. There is no reliable cure. Remove affected fish promptly to protect the rest of the group, and keep water quality high, as stressed fish are more vulnerable.
White spot
Small white dots over the body and fins, often after a temperature drop or the arrival of new fish. It is treatable with a proprietary white spot remedy if caught early. Follow the dosing carefully, as tetras are sensitive to some medications.
Colour loss
Neons fade at night and when stressed, which is normal. Colour that stays faded during the day usually points to poor water quality, too small a group, bright lighting or a pale substrate.
Breeding Neon Tetras
Neons are egg scatterers and are one of the trickier common fish to breed at home. It is achievable, but it takes a dedicated setup:
- Set up a small breeding tank of 20 to 30 litres with very soft, acidic water (pH around 5.5 to 6.0) at 24 to 25°C.
- Keep it almost dark, with a spawning mop or fine-leaved plants such as java moss.
- Condition a pair or small group with live and frozen foods for a week or two. Females are rounder in the belly; males are slimmer with a straighter blue stripe.
- Introduce them in the evening. Spawning usually happens the next morning.
- Remove the adults straight after spawning, as they will eat the eggs.
- Keep the tank dark; the eggs are light sensitive. They hatch in about 24 hours, and the fry are free swimming a few days later. Feed infusoria at first, then baby brine shrimp.
Buying and Acclimatising Neon Tetras
When you buy neons, look for fish that are swimming actively in a group, with bright, unbroken colour and no white spots, ragged fins or bent spines. On arrival, acclimatise them slowly. Neons are sensitive to sudden changes in pH and temperature, so the drip method is the safest choice; our drip acclimatisation guide walks you through it step by step. Keep the lights off for the rest of the day and feed lightly the next morning.
All our livestock is delivered by tracked courier in insulated packaging. You can see the whole range of shoaling species, along with our neon tetras, in the tetra category.
Frequently Asked Questions
How many neon tetras should I keep?
At least six, and ideally ten or more. Larger groups are calmer, more colourful and live longer.
Can neon tetras live with bettas?
Sometimes. In a well-planted tank of 54 litres or more, many bettas ignore neons. Some bettas are aggressive, though, so have a backup plan.
Do neon tetras need a heater?
Yes. In a UK home, room temperature drops well below their comfortable range, particularly overnight and in winter.
Why are my neon tetras dying?
The most common causes are adding them to an uncycled tank, sudden water changes, poor water quality and keeping too few. Test your water first; ammonia or nitrite above zero is the usual culprit.
How long do neon tetras live?
Typically around five years, and sometimes longer in a stable, well-maintained tank kept at the cooler end of their range.
Neon tetras reward a little patience with years of colour and movement. Choose a mature tank, keep a proper shoal, and they will become the centrepiece of a peaceful community. For help choosing between all the shoaling species we stock, read our guide to choosing the right tetra fish.