Neon Tetra Care Guide: Tank Setup, Diet, Health, and Tank Mates

The neon tetra (Paracheirodon innesi) is one of the most popular freshwater aquarium fish in the world. Native to the blackwater streams of the Amazon basin in South America, these small schooling fish are recognized instantly by their iridescent blue stripe and vivid red tail. They were first imported to Europe in the 1930s and have been a staple of the aquarium hobby ever since.

Neon tetras appeal to both beginners and experienced fishkeepers because they are peaceful, hardy once established, and strikingly colorful for their size. A school of neon tetras moving in unison through a planted tank is one of the most satisfying sights in the hobby. They stay small at just 1.5 inches, produce a low bioload, and coexist peacefully with a wide range of tank mates.

This guide covers everything you need to keep neon tetras healthy and thriving: tank setup, water parameters, diet, compatible tank mates, schooling requirements, common diseases, and breeding basics.

Neon Tetra at a Glance

Tank Setup

Neon tetras need a minimum of 10 gallons for a school of 6 fish. While they are small, they are active swimmers that use the full length of the tank, and a 10-gallon aquarium provides just enough horizontal swimming space. A 20-gallon tank is the better choice if you want a larger school of 10 to 15 neon tetras or plan to keep them in a community setup with other species.

Substrate

While most aquarium substrates will work, dark substrates mimic the tannin-stained riverbeds of their native Amazon habitat and bring out noticeably stronger blue and red coloration — neon tetras on light substrates look washed out by comparison.

• Black sand — best choice if keeping with corydoras or other bottom-dwellers that sift the substrate.
• Fine dark gravel — works well for neon-only setups. Avoid anything sharp or coarse.
• Planted tank soil (Fluval Stratum, ADA Amazonia) — lowers pH and softens water naturally, which neon tetras prefer. Ideal if you’re running a planted tank.

Bare-bottom tanks are fine for quarantine or breeding, but neon tetras show more natural behavior with substrate — they feel more secure and school more calmly.

Plants and Decoration

Neon tetras thrive in planted tanks. Live plants serve multiple purposes: they provide cover that reduces stress, break sight lines, and help maintain water quality by absorbing nitrates. Good plant choices include Java fern, Amazon sword, Anubias, and Vallisneria. Floating plants like Water Lettuce or Salvinia are particularly effective because they dim the lighting, which neon tetras prefer.

Lighting

Neon tetras come from shaded forest streams and prefer subdued lighting. Bright, direct aquarium lights can stress them and fade their colors. If your light is intense, floating plants or dimmer settings will create the conditions they prefer. Their blue stripe is iridescent — created by light reflecting off cells rather than by pigment — so it actually looks more vivid under moderate, angled lighting than under harsh overhead light.

Water Parameters

Stable water conditions matter more than hitting exact numbers. Neon tetras tolerate a range of parameters, but sudden changes in temperature, pH, or hardness cause stress and weaken their immune system.

Temperature

Set your heater to 73-77°F (23-25°C) for the best balance of color, activity, and long-term health. The full tolerance range is 68 to 82°F (20 to 28°C).

• Below 70°F — Too cool for long-term care. Activity drops and immune function weakens.
• 73-77°F — Ideal. Best coloration, active schooling, and strong immunity.
• Above 79°F — Increases metabolism. Extended exposure can shorten lifespan.

Use an adjustable heater with a separate thermometer to verify accuracy — built-in thermostats can drift. Even in warm climates, nighttime drops can stress neon tetras.

pH

Aim for pH 6.0-7.5. Captive-bred neon tetras tolerate a wide range, but stability matters more than hitting a specific number.

• Below 5.0 — Extreme blackwater territory. Wild neon tetras survive here, but unnecessary for captive-bred fish.
• 6.0-7.5 — Ideal for captive-bred stock. No need to adjust your tap water if it falls in this range.
• 7.5-8.0 — Still tolerated well by captive-bred fish, as long as the pH stays stable. Don’t chase lower numbers with chemical buffers.

Avoid sudden pH swings — a stable 7.5 is far safer than a pH that bounces between 6.5 and 7.0 from buffer dosing.

Hardness

Target 5-10 dGH. Neon tetras prefer soft water, but captive-bred stock handles a broader range than wild fish.

• 1-2 dGH — Wild habitat levels. Only needed for breeding setups.
• 5-10 dGH — Ideal for captive-bred neon tetras in a community tank.
• 10-15 dGH — Tolerated, but keep it stable. Avoid mixing hard and soft water sources.

Carbonate hardness (KH) of 1 to 4 dKH helps buffer pH against sudden swings.

Filtration

Any standard aquarium filter works — sponge, hang-on-back, canister — as long as the flow isn’t pushing your tetras around. Neon tetras come from slow-moving streams and prefer calmer water, so gentle flow is the main thing to get right.

Aim for 4 to 6 times tank volume turnover per hour. If you notice tetras struggling against the current or avoiding one side of the tank, reduce the flow rate or baffle the output.

Diet and Feeding

Neon tetras are omnivores that eat a wide variety of foods. In the wild, they feed on tiny insects, insect larvae, small crustaceans, algae, and fallen plant matter. A varied diet in captivity keeps them healthy and brings out their best coloration.

What to Feed

How Often to Feed

Feed neon tetras twice per day in small amounts they can finish within 1 to 2 minutes. Their stomachs are roughly the size of their eye, so overfeeding is easy and dangerous. Uneaten food decomposes, spikes ammonia levels, and degrades water quality fast — especially in smaller tanks. If food is settling to the bottom uneaten, you are feeding too much.

Tank Mates

Neon tetras are peaceful, non-territorial fish that do well in community tanks — as long as their tank mates share similar temperament and size. The key rule: anything large enough to fit a neon tetra in its mouth will eventually eat one.

Compatible Species

Neon tetras can sometimes work as betta tank mates in tanks of 15 gallons or larger. Their speed helps them avoid betta aggression, but success depends entirely on the individual betta’s temperament. Cherry shrimp also make excellent companions, adding bottom-level activity and color without competing for food or space.

Species to Avoid

Behavior and Schooling

Neon tetras are obligate schooling fish. They need a group of at least 6 individuals to feel secure, and groups of 10 or more produce the best schooling behavior and coloration. A neon tetra kept alone or in a group of 2 to 3 will be visibly stressed — hiding constantly, refusing food, losing color, and becoming susceptible to disease.

Why Schooling Matters

In the wild, neon tetras school as protection against predators. A tight-moving group confuses predators and makes it harder to single out one fish. This instinct is hardwired. Even in a predator-free aquarium, neon tetras that cannot school experience chronic stress that shortens their lifespan and weakens their immune response.

A well-established school of neon tetras displays fascinating synchronized movement. They will move through the tank in formation, change direction together, and cluster tightly when startled. In larger schools of 15 or more, you will see distinct subgroups form and merge throughout the day.

Signs of Stress

If you notice these behaviors, check water parameters first. If water quality is fine, the school size may be too small, the lighting too bright, or a tank mate may be causing intimidation.

Why Is My Neon Tetra Losing Color?

If it happens when the lights come on, it’s normal. Neon tetras fade their coloration while resting as a natural defense — it makes them less visible to predators in the dark. Full color returns within minutes of the lights turning back on.

If colors stay faded during the day, something else is going on:

• Water quality — Ammonia or nitrite above zero, or a sudden pH swing. Test your water first.
• Stress — School too small (under 6), aggressive tank mates, or lighting too bright.
• Temperature — Too cold slows metabolism and dulls coloration. Check your heater is holding 73-77°F.
• Neon tetra disease — Fading color that progresses to white patches, especially along the spine. No cure — remove affected fish immediately. See the health section below.

The quick rule: pale at lights-on is normal. Pale during the day with changes in behavior means investigate.

Common Health Issues

Neon tetras are generally hardy once established, but they are vulnerable to a few specific diseases. Most health problems trace back to poor water quality, stress, or introducing sick fish without quarantine.

Neon Tetra Disease (NTD)

Neon tetra disease is the most serious illness specific to this species. It is caused by the microsporidian parasite Pleistophora hyphessobryconis and has no known cure. The parasite enters the fish through ingestion of infected material — typically dead fish, contaminated live food, or spores in the water column.

Symptoms progress in stages:

1. Restlessness and separation from the school
2. Gradual fading of the blue and red coloration
3. White or pale patches appearing on the body as muscle tissue is destroyed
4. Difficulty swimming and maintaining balance
5. Curved or bent spine in advanced cases
6. Secondary infections (fin rot, bloating) as the immune system collapses

Prevention is the only defense:

• Quarantine all new fish for 2 to 3 weeks before adding them to your main tank
• Remove dead fish from the tank immediately
• Avoid feeding live Tubifex worms, which can carry the parasite
• Buy from reputable sources that quarantine their own stock
• Maintain excellent water quality to keep immune systems strong

False Neon Tetra Disease (Columnaris)

Columnaris is a bacterial infection that mimics NTD symptoms, including white patches and color fading. The key difference is that columnaris often presents with white cottony growths around the mouth or body, and it progresses faster. Unlike true NTD, columnaris can be treated with antibiotics (kanamycin or nitrofurazone) if caught early.

Ich (White Spot Disease)

Ich is a common parasitic infection recognizable by small white dots that look like grains of salt on the body and fins. Neon tetras are susceptible to ich, especially after temperature changes or stress events. Treatment involves gradually raising the water temperature to 82°F over 24 to 48 hours and using an ich medication containing malachite green or formalin. Remove carbon from the filter during treatment.

Fin Rot

Fin rot presents as frayed, discolored, or receding fin edges. It is almost always caused by poor water quality and can be reversed with improved tank maintenance. Perform daily 20% water changes, ensure the filter is working properly, and treat with a broad-spectrum antibacterial if the condition does not improve within a week.

Buying Healthy Neon Tetras

The quality of your initial stock matters enormously. Mass-bred neon tetras from large fish farms can be weaker and more disease-prone than selectively bred fish from smaller breeders.

Ask the store how long the fish have been in stock. Neon tetras that have been at the store for at least one to two weeks have already survived the most stressful phase of transport and acclimation. Avoid buying fish that arrived the same day or are still in shipping bags.

Sources

• FishBase — Paracheirodon innesi species profile. Temperature, pH, and hardness reference ranges.
• SeriouslyFish — Paracheirodon innesi care profile. Detailed habitat data and husbandry notes.
• Burkhart, Crow & Keeley — Pocket Guide to the Care and Maintenance of Aquarium Fish. Water parameter recommendations including captive-bred tolerances.

Frequently Asked Questions