Kennedy’s Tetra

Quick Summary

Kennedy’s Tetra is a peaceful, hardy shoaling characin that does well in most community tanks, making it a solid choice for beginners and experienced keepers alike provided it is kept in groups of six or more.

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In this guide:

• Introduction
• Quick Stats
• Appearance
• Natural Habitat
• Tank Size and Setup
• Water Parameters
• Diet and Feeding
• Behaviour and Temperament
• Tank Mates
• Breeding

Introduction

Kennedy’s Tetra (Ctenobrycon kennedyi) is a relatively understated South American characin that deserves far more attention than it typically receives in the hobby. While it lacks the vivid neon flash of some of its more famous relatives, it makes up for this with a quiet elegance, robust constitution, and an exceptionally peaceful temperament that makes it one of the easiest tetras to house in a mixed community setting.

For many years this species was classified as Psellogrammus kennedyi, and you will still find it listed under that name in many shops, online retailers, and older reference books. A recent taxonomic revision moved it into the genus Ctenobrycon, so both names refer to the same fish. If you see either label on a stocklist, you are looking at the same species. Throughout this guide we use the current accepted name, Ctenobrycon kennedyi.

Native to slow-moving waterways in South America, Kennedy’s Tetra is an adaptable species that tolerates a fairly broad range of water chemistry, which is one of the reasons it is so well suited to community aquaria. It is an obligate shoaler – keeping a group of at least six is essential to see natural behaviour and reduce stress. In a well-planted tank with gentle filtration and compatible tank mates, a shoal of Kennedy’s Tetras will reward the keeper with lively, coordinated schooling displays and very few care headaches.

Appearance

Kennedy’s Tetra has the classic deep-bodied, laterally compressed shape characteristic of many characins in the Ctenobrycon group. It is noticeably deeper in the body than slimmer tetras such as neons or cardinals, giving it a somewhat stocky yet graceful silhouette. Adults typically reach 5 to 6 centimetres in standard length, with females tending towards the upper end of that range when in breeding condition.

The base body colour is a silvery-olive, often with a subtle golden or greenish sheen under good lighting. A faint dark lateral stripe runs from behind the gill cover to the base of the caudal fin, terminating in a small but distinct dark blotch on the caudal peduncle. This marking can vary in intensity depending on the fish’s mood, health, and lighting conditions. The fins are largely transparent to slightly yellowish, and the anal fin is relatively long and gently curved – a feature that helps distinguish the genus from superficially similar tetras.

Males and females are not dramatically different in colour, but experienced keepers can sex adults with reasonable confidence. Males are generally slimmer and may display slightly more intense colouration, especially along the dorsal and anal fins. Females tend to be rounder in the belly, particularly when carrying eggs, and their body depth is proportionately greater. Under optimal conditions with a varied diet, both sexes can develop a subtle iridescent quality that is best appreciated in a dimly lit, well-planted aquarium.

Juvenile Kennedy’s Tetras are paler and lack the full depth of body seen in adults. The caudal spot is present from an early age and serves as a useful identification feature when buying young fish that may otherwise look generic among the many small silver tetras available in the trade.

Natural Habitat

Kennedy’s Tetra is found in freshwater systems of northern South America, primarily within the Magdalena River basin in Colombia and waterways associated with the Lake Maracaibo basin in Venezuela. These are warm, tropical lowland drainages that experience seasonal fluctuations in water level and flow.

In the wild, this species inhabits slow-moving rivers, tributaries, and associated floodplain habitats. The water in these areas is typically warm, slightly acidic to neutral, and moderately soft, though conditions can vary considerably between the dry and wet seasons. The substrate is often sandy or muddy with accumulations of leaf litter, fallen branches, and submerged vegetation that provide shelter and foraging opportunities.

Kennedy’s Tetras are found in areas with overhanging riparian vegetation that dapples the light and provides a degree of cover from avian predators. Aquatic plants, including floating species and emergent grasses, are common features of their habitat. Understanding these conditions helps explain the fish’s preferences in captivity: gentle flow, subdued lighting, plenty of plant cover, and soft to moderately hard, slightly acidic water.

In nature, Kennedy’s Tetras form loose shoals that move through the water column picking at small invertebrates, algae, and organic detritus. They share their habitat with a wide variety of other characins, cichlids, catfish, and other freshwater species, reinforcing their suitability for community aquaria.

Tank Size and Setup

A group of six Kennedy’s Tetras requires a minimum tank volume of 80 litres. If you plan to keep a larger shoal – which is always preferable for shoaling species – or wish to house them in a community with other species, aim for 120 litres or more. The additional swimming space reduces stress, makes schooling behaviour more pronounced, and provides a buffer for water quality management.

Choose a tank with a rectangular footprint rather than a tall, narrow design. Kennedy’s Tetras occupy primarily the mid-water column but will explore all levels of the aquarium, and a longer tank gives them the horizontal swimming room they need. A standard 80-centimetre or 90-centimetre tank is ideal for a small community centred around this species.

Planting the aquarium is highly recommended. Dense planting along the sides and back of the tank provides shelter and mimics the vegetated margins of their natural habitat. Good choices include Vallisneria, Cryptocoryne species, Java Fern, and Anubias. Floating plants such as Amazon Frogbit or Salvinia are particularly beneficial because they diffuse overhead lighting and help the fish feel secure. Leave an open swimming area in the front and centre of the tank to allow the shoal to school freely.

The substrate can be fine sand or smooth gravel – Kennedy’s Tetras are not bottom dwellers and have no special substrate requirements. A dark substrate will show off their subtle colouration better than a pale one. Adding a few pieces of driftwood and some dried leaf litter (Indian Almond leaves work well) will help create a natural look, gently acidify the water, and provide surfaces for biofilm growth that the fish may graze on.

A secure lid is essential. Like many tetras, Kennedy’s Tetras can and do jump, particularly when startled. A well-fitting cover glass or hood prevents losses and also helps maintain stable temperature and humidity above the water surface.

Lighting should be moderate. If you are growing live plants that require higher light levels, ensure the floating plants mentioned above are present to create shaded areas. The fish will naturally gravitate to these dimmer zones and will display more confident behaviour as a result.

Water Parameters

Kennedy’s Tetra is a tolerant species that accepts a fairly wide range of water chemistry, which is a significant advantage for beginners. Nevertheless, keeping conditions stable and within the optimal range will promote the best health, colouration, and longevity.

The ideal temperature for most community setups containing Kennedy’s Tetras is around 25 to 26 C. This sits comfortably within the preferred range for many common tank mates. Avoid sustained temperatures above 28 C, as this reduces dissolved oxygen and can stress the fish over time.

A slightly acidic to neutral pH of 6.5 to 7.0 is ideal, though the species will thrive across the full range listed above. If your tap water is moderately hard and slightly alkaline, Kennedy’s Tetras will usually adapt without issue provided the transition is gradual and the parameters remain stable.

Ammonia and nitrite must always read zero in a mature aquarium. These compounds are toxic to fish at any detectable level. If you are seeing readings above zero, investigate your biological filtration and stocking levels immediately. Nitrate should be kept below 20 ppm through regular partial water changes – a 25 to 30 per cent change weekly is a good routine for most setups.

Consistency matters more than hitting a precise number. Sudden swings in pH or temperature are far more harmful than a stable reading that sits slightly outside the textbook ideal. Use a reliable liquid test kit to monitor your water regularly, especially in the first few months after setting up a new tank or adding new fish.

Filtration and Equipment

Kennedy’s Tetras come from slow-moving waters and do not appreciate strong currents. Choose a filter that provides adequate biological and mechanical filtration without creating a powerful flow. A hang-on-back filter rated for the tank’s volume, or a small canister filter with an adjustable outlet, works well. Sponge filters are another excellent option, particularly in breeding setups, as they provide gentle flow and pose no risk to fry.

If you are using a canister or hang-on-back filter with a strong output, direct the return flow against the back glass or use a spray bar to diffuse it. This allows the filter to turn over the tank volume adequately – aim for four to six times the tank volume per hour – without blasting the fish with a current they must constantly fight against.

An adjustable heater rated for the tank size is necessary to maintain a stable tropical temperature. Place it near the filter outlet so that warmed water is distributed evenly throughout the tank. Always use a separate thermometer (digital or analogue) to verify the heater’s accuracy, as built-in thermostats can drift over time.

Standard aquarium lighting suitable for growing low to moderate-light plants is perfectly adequate. Kennedy’s Tetras do not require any specialised lighting. If anything, err on the side of softer illumination, supplemented by floating plants, to bring out the best in the fish’s behaviour and subtle colouration.

An air pump is not strictly necessary if the filter provides sufficient surface agitation for gas exchange, but it can be a useful backup during warm weather when dissolved oxygen levels drop. A gentle airstone in one corner of the tank provides additional oxygenation without creating excessive turbulence.

Diet and Feeding

Kennedy’s Tetra is an omnivore with a leaning towards small invertebrates and organic matter. In captivity, it is an enthusiastic and unfussy eater that will accept a wide variety of foods. A balanced diet is the key to good health, strong colouration, and successful breeding.

A high-quality micro-pellet or flake food formulated for tropical community fish should form the staple of the diet. Look for products with whole fish or insect meal listed as the first ingredient rather than grain or cereal fillers. Feed an amount the fish can consume within two to three minutes, once or twice daily. It is better to underfeed slightly than to overfeed, as uneaten food degrades water quality.

Supplement the staple diet with live or frozen foods two to three times per week. Excellent choices include daphnia, baby brine shrimp (Artemia nauplii), cyclops, bloodworm (in moderation), and micro-worms. These foods provide essential nutrients, encourage natural foraging behaviour, and are particularly important for conditioning fish for breeding.

Vegetable matter should not be overlooked. Blanched spinach, crushed spirulina flakes, or algae wafers broken into small pieces provide fibre and micronutrients. In a well-planted tank, the fish will also graze on biofilm and soft algae growing on surfaces, which contributes to their overall nutritional intake.

Variety is genuinely important. Rotating between three or four different food types across the week ensures that no single nutritional gap persists. Fasting the fish for one day per week is a common practice among experienced keepers and can benefit digestion, though it is not strictly necessary.

Behaviour and Temperament

Kennedy’s Tetra is a peaceful, sociable species that poses no threat to any similarly sized or tempered tank mate. It is a true shoaling fish, meaning it draws comfort and confidence from the presence of conspecifics. A minimum group of six is essential; eight to twelve is preferable. In smaller numbers, the fish become shy, stressed, and prone to hiding, and may occasionally nip at the fins of other species out of anxiety – a behaviour that virtually disappears in a properly sized group.

Within the shoal, you may observe occasional minor sparring between males, particularly around feeding time. This typically manifests as brief chasing or flared fins and is entirely normal. No physical harm results, and these interactions help establish a loose social hierarchy. Providing adequate space and line-of-sight breaks (plants, wood) ensures that no individual is persistently harassed.

Kennedy’s Tetras primarily occupy the middle water column but will explore all levels of the tank. They are active during the day, swimming in a loose, coordinated group that tightens into a denser school when they feel threatened. This schooling response is one of the most attractive aspects of keeping them – it is a genuinely engaging behaviour to observe.

The species is not territorial and does not defend any particular area of the tank. It coexists peacefully with bottom dwellers, surface dwellers, and other mid-water species, making it one of the more straightforward tetras to integrate into a community setup. It is not a plant eater and will not damage aquarium vegetation.

Stress indicators to watch for include persistent hiding, loss of colour, clamped fins, or erratic swimming. These behaviours usually point to poor water quality, insufficient group size, aggressive tank mates, or inadequate cover in the tank. Addressing the root cause typically resolves the issue quickly, as Kennedy’s Tetras are resilient and recover well from short-term stress.

Tank Mates

Kennedy’s Tetra is one of the more accommodating community fish available. Its peaceful nature, moderate size, and preference for mid-water swimming make it compatible with a very wide range of species. The main considerations when choosing tank mates are to avoid anything large enough to eat them, anything overly aggressive or territorial, and anything so small or slow that the tetras might outcompete it for food.

Good tank mates

• Cardinal Tetra – Another peaceful South American shoaler that occupies similar water parameters and adds a striking colour contrast.
• Rummy-Nose Tetra – Shares the same preference for warm, soft water and schools beautifully alongside Kennedy’s Tetras.
• Ember Tetra – A small, peaceful tetra that stays in the mid to upper water column and will not compete aggressively for food.
• Corydoras sterbai – A warm-water-tolerant Corydoras that peacefully scavenges the bottom, complementing the tetras’ mid-water activity.
• Bronze Corydoras – Hardy, peaceful bottom dwellers that make excellent companions in any community tank.
• Kuhli Loach – A shy, nocturnal bottom dweller that will not interact with or bother the tetras in any way.
• Cherry Barb – A gentle barb species that mixes well with tetras and adds warm colour to the tank.
• Honey Gourami – A calm, small gourami that inhabits the upper water column and coexists peacefully with tetras.
• Bristlenose Pleco – A practical algae-eating catfish that minds its own business and is compatible in terms of temperament and water parameters.
• Amano Shrimp – Large enough to avoid predation by Kennedy’s Tetras and an excellent clean-up crew member.

Fish to avoid

• Oscar – A large, predatory cichlid that will readily eat Kennedy’s Tetras.
• Jack Dempsey – An aggressive cichlid far too territorial and large for a tetra community.
• Red-Tail Catfish – Grows enormous and is a voracious predator of anything that fits in its mouth.
• Green Terror – A highly territorial and aggressive cichlid that will harass or consume small tetras.
• Tiger Barb – Notorious fin nippers that can relentlessly harass tetras, especially in insufficient numbers.
• African Cichlids (Mbuna) – Require hard, alkaline water and are far too aggressive for a tetra community.
• Red-Bellied Piranha – An obvious predator that should never be housed with small community fish.

Breeding

Breeding Kennedy’s Tetra in captivity is achievable but requires some preparation and a dedicated breeding setup. The species is an egg scatterer, meaning the adults broadcast eggs among fine-leaved plants or spawning mops and provide no parental care. In fact, the adults will readily eat their own eggs and fry if given the opportunity, so separation is essential.

To condition a breeding group, select the healthiest, most vibrantly coloured males and the plumpest females from your main tank. Feed them a high-protein diet of live or frozen foods – baby brine shrimp, daphnia, and bloodworm – for one to two weeks before attempting to spawn them. This dietary enrichment encourages egg development in females and sperm production in males.

Set up a separate breeding tank of approximately 30 to 40 litres. The water should be soft (2 to 6 dGH), slightly acidic (pH 6.0 to 6.5), and warm (26 to 27 C). Use a mature sponge filter for gentle filtration and low flow. Cover the bottom of the tank with a layer of glass marbles, a mesh screen, or dense clumps of Java Moss – the goal is to allow eggs to fall through to a protected space where the adults cannot reach them.

Introduce one or two pairs into the breeding tank in the evening. Spawning typically occurs at first light the following morning. The male will court the female with short chasing displays, and the pair will release eggs and milt simultaneously among the plants or over the substrate. A single spawning can produce several hundred small, semi-adhesive eggs.

Remove the adults immediately after spawning to prevent egg predation. The eggs are small and translucent, and they will hatch in approximately 24 to 36 hours depending on temperature. The fry become free-swimming roughly three to four days after hatching, once the yolk sac is absorbed.

First foods for the fry should be infusoria or commercially available liquid fry food. After a week or so, they can graduate to freshly hatched baby brine shrimp and microworms. Growth is steady, and the fry can typically be moved to a grow-out tank or carefully introduced to the main community once they are large enough not to be eaten by adult fish – usually at around 1.5 to 2 centimetres in length.

Keep the breeding and fry tanks scrupulously clean with small, frequent water changes using water matched to the tank’s temperature and chemistry. The fry are sensitive to poor water quality in their first weeks of life.

Common Diseases

Kennedy’s Tetra is a hardy species that is not especially prone to disease when kept in clean, stable conditions. However, like all freshwater fish, it can fall victim to several common ailments, particularly when stressed by poor water quality, overcrowding, or sudden environmental changes.

Ich (White Spot Disease) is perhaps the most frequently encountered illness in tropical aquaria. It presents as small white cysts on the fins and body, and affected fish may flash (rub against objects) or clamp their fins. Ich is caused by the protozoan parasite Ichthyophthirius multifiliis and is highly contagious. Treatment involves gradually raising the water temperature to 28 to 30 C and administering a proprietary white spot medication according to the manufacturer’s instructions. Tetras can be sensitive to some medications containing copper or formalin, so choose a product labelled as safe for scaleless or sensitive fish, and always dose carefully.

Fin rot is a bacterial condition that manifests as fraying, discolouration, or erosion of the fins. It is almost always secondary to poor water quality or physical injury. Improving water conditions through increased water changes is the first and most important step. In severe cases, a broad-spectrum antibacterial treatment may be necessary.

Columnaris (sometimes called mouth fungus or cotton wool disease) is a bacterial infection that produces white or greyish patches on the mouth, body, or fins. It can progress rapidly if untreated. Antibacterial medications effective against gram-negative bacteria are the standard treatment, alongside improving water quality.

Internal parasites can occasionally affect wild-caught or recently imported specimens. Symptoms include weight loss despite a healthy appetite, white or stringy faeces, and a generally emaciated appearance. Medicated food containing anti-parasitic compounds is the usual treatment approach.

Neon Tetra Disease (NTD), caused by the microsporidian parasite Pleistophora hyphessobryconis, can affect various tetra species, not just neon tetras. Symptoms include loss of colour, cysts or lumps beneath the skin, erratic swimming, and progressive wasting. Unfortunately, there is no reliable cure for NTD. Affected fish should be promptly removed from the community to prevent transmission.

Prevention is always better than cure. Quarantine all new fish for at least two to three weeks before adding them to an established tank. Maintain excellent water quality, avoid overstocking, and feed a varied, nutritious diet. These simple measures dramatically reduce the likelihood of disease outbreaks.

FAQs

Is Kennedy’s Tetra the same as Psellogrammus kennedyi?

Yes. The species was formerly classified as Psellogrammus kennedyi, but a taxonomic revision has moved it to the genus Ctenobrycon. Both names refer to the same fish, and you may encounter either in shops, online listings, and older literature. Ctenobrycon kennedyi is the current accepted scientific name.

How many Kennedy’s Tetras should I keep together?

A minimum of six is required, but eight to twelve is strongly recommended. Larger groups display more natural, relaxed behaviour, school more cohesively, and are less likely to show any fin-nipping tendencies. In a sufficiently large tank, there is no real upper limit – a shoal of twenty or more is a spectacular sight.

Can Kennedy’s Tetras live with shrimp?

Adult Amano Shrimp and other larger shrimp species are generally safe with Kennedy’s Tetras. However, very small shrimp such as newly born Cherry Shrimp or small Neocaridina may be at risk of predation, as the tetras will opportunistically eat anything small enough to fit in their mouths. If you keep breeding shrimp colonies, provide dense plant cover to give shrimplets hiding spots.

Do Kennedy’s Tetras need a heater?

Yes. Kennedy’s Tetra is a tropical species that requires a stable water temperature of 23 to 28 C. In most households, an aquarium heater is necessary to maintain this range consistently, especially during cooler months. Even in warm climates, a heater provides an important buffer against overnight temperature drops.

Why are my Kennedy’s Tetras losing colour?

Colour loss in tetras is usually a sign of stress. Common causes include poor water quality (check ammonia, nitrite, and nitrate), insufficient group size, aggressive tank mates, inadequate cover or hiding spots, recent transport or acclimation, or the onset of disease. Address the underlying issue, and colour should return within days to a couple of weeks. A varied, high-quality diet also plays an important role in maintaining vibrant colouration.

Related Guides

• Cardinal Tetra Care Guide – A popular South American tetra with similar care requirements, ideal for the same community setups.
• Rummy-Nose Tetra Care Guide – Another excellent shoaling tetra that pairs beautifully with Kennedy’s Tetras in planted tanks.
• Corydoras sterbai Care Guide – A warm-water Corydoras that makes a perfect bottom-dwelling companion for this species.
• Honey Gourami Care Guide – A peaceful gourami that complements tetras well and adds variety to the upper water column.
• Cherry Barb Care Guide – A gentle, colourful barb that thrives under the same conditions as Kennedy’s Tetra.