−15%
Easy
Black Ruby Barb (Pethia nigrofasciata)
20–26°C · pH 6–7.5 · 80L
£2.54£2.99
A fast, eye-catching shoaling fish with a bold red line and torpedo-shaped silver body, ideal for spacious river-style community aquariums. Best kept in groups of 6+. Order today with UK live arrival guarantee.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Puntius denisonii
Denison Barb are a shoaling species — they need 6+ to feel safe and show their full colour.
A fast, eye-catching shoaling fish with a bold red line and torpedo-shaped silver body, ideal for spacious river-style community aquariums. Best kept in groups of 6+. Order today with UK live arrival guarantee.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Photos are AI-enhanced, so the animal may show subtle colour or marking differences.
Maintain these water conditions for optimal health and vibrant colors
The Denison Barb, also sold as the Red-Line Torpedo Barb, Miss Kerala barb, or roseline shark, is one of the most eye-catching shoaling fish available for a large tropical aquarium. Known scientifically as Puntius denisonii (now widely reclassified as Sahyadria denisonii, and historically traded as Dawkinsia denisonii), this fast-swimming barb comes from clear, oxygen-rich rivers in southern India and combines a sleek silver body, a bold scarlet stripe, and a sharp black lateral line in one unforgettable fish. Adult denison barb size typically reaches around 12 cm, though a well-grown specimen can look larger because of its long, torpedo-shaped body. With proper care, a denison barb lifespan of 6-8 years is realistic, making it a rewarding long-term choice for aquarists who want a peaceful but active centrepiece shoal.
This is not a fish for tiny tanks or casual impulse buys. The denison barb minimum tank size starts at 200 litres, and the ideal setup is even larger because denison barb school size matters so much to behaviour and confidence. If you have searched for a denison barb care guide, wondered about denison barb growth rate, or asked how many denison barbs should be kept together, this page answers those questions in practical detail. Our detailed photos show the clean red line, yellow tail flashes, and streamlined body shape that make this species a standout. For fishkeepers building a high-energy river-style community, this is one of the best barbs for a high-flow tank and a superb choice for a denison barb for large community tank setup.
The Denison Barb belongs to the carp and barb family, Cyprinidae. It became famous because it offers the speed and schooling behaviour of classic barbs without the heavy fin-nipping reputation of some smaller species. A larger, generally less suitable relative, Sahyadria chalakkudiensis, is sometimes confused with it in online searches, but the true Denison Barb is the slimmer, more elegant aquarium species described here.
The Denison Barb is native to the Western Ghats of India, especially river systems in Kerala and Karnataka. In the wild, this species inhabits fast-flowing hill streams and river channels with high oxygen levels, rocky or sandy bottoms, and clean, moving water. These habitats explain why denison barb flow requirements are higher than many community fish, and why a sluggish, under-filtered aquarium rarely shows this species at its best.
Unlike many mass-market aquarium fish, the Denison Barb has a conservation story. Wild populations have been pressured by habitat change and historical over-collection for the ornamental trade, so responsible fishkeepers should prioritise captive-bred stock. If you are looking for a denison barb for sale UK or want to buy Dawkinsia denisonii UK, choosing healthy captive-bred fish supports more sustainable fishkeeping.
In nature, these fish move in groups through open water, feeding on insect larvae, small crustaceans, organic matter, and plant material. That natural feeding pattern shapes the broad denison barb diet in captivity: they are not strict herbivores, but they do appreciate some vegetable matter. Aquarists often ask whether denison barbs eat plants; in a well-fed aquarium they may nibble very soft growth or biofilm, but they are rarely destructive.
Mimicking the natural habitat of the Denison Barb means prioritising flow, oxygen, and horizontal swimming space. In our experience, these barbs colour up faster and settle better in long tanks with visible current than in tall, still aquariums of the same volume.
The first question most buyers ask is simple: what is the correct denison barb tank size? The absolute denison barb minimum tank size is 200 litres, but that should be treated as a starting point for a young group rather than an ideal forever home. Because this species is a powerful midwater swimmer, a tank length of at least 120 cm is strongly recommended. For a settled adult shoal, 240 litres or more gives better swimming room, reduces stress, and improves social behaviour.
Aim for at least 6 denison barbs, with 8-10 even better in larger systems. A small group can become nervous, skittish, or pushy at feeding time. A proper denison barb school size spreads out social tension and creates the flowing, coordinated movement that makes this species so desirable among schooling fish UK hobbyists. You can see more of our active group species on the schooling fish hub.
The ideal denison barb temperature range is 20-25°C, with a denison barb ideal temperature around 22-24°C for most community setups. This slightly cooler tropical range suits their river origin well. Keep the denison barb pH level between 6.5 and 7.8, and hardness around 5-15 dGH. Stability matters more than chasing an exact number; sudden swings in pH or temperature can cause stress and increase disease risk.
Strong filtration is essential. The correct torpedo barb flow requirements and denison barb flow requirements are best met with an external canister filter or a high-quality internal filter that turns over the tank volume several times per hour. Add a spray bar or powerhead if needed to create visible current without blasting every corner of the tank. The goal is steady movement and high dissolved oxygen, not chaos.
Use smooth gravel or sand with rounded stones and driftwood. A denison barb planted tank can work very well; choose hardy plants that tolerate flow, such as Java fern, Anubias, Vallisneria, and attached mosses, and leave broad open swimming areas through the middle. This species also makes an excellent torpedo barb for planted aquarium display when the layout balances cover and open water.
Always cycle the aquarium for 4-6 weeks before adding Denison Barbs. Because they are active and oxygen-demanding, they react badly to immature filters and any detectable ammonia or nitrite.
The denison barb diet is omnivorous and should be varied. In the wild they pick at insect larvae, tiny crustaceans, plant matter, and biofilm. In captivity, the best results come from a mix of quality micro pellets, flake, frozen foods, and occasional vegetable matter. This broad feeding style is one reason they adapt well to community tanks, provided they are not outcompeted by very aggressive feeders.
Use a high-quality tropical pellet or flake as the daily base. Choose foods rich in marine proteins and spirulina rather than cheap fillers.
Offer frozen bloodworm, brine shrimp, daphnia, and mosquito larvae two to four times per week. These foods improve body condition and support colour. Blanched spinach, shelled peas, and spirulina-based foods can also be included. If denison barbs are underfed they may nibble tender leaves, so regular vegetable inclusion helps reduce curiosity damage.
| Time | Food | Amount |
|---|---|---|
| Morning | Quality tropical pellet or flake | Only what the group clears in 1-2 minutes |
| Evening | Frozen bloodworm, brine shrimp, or spirulina food | Small portion, no leftovers after 2 minutes |
Overfeeding causes ammonia spikes, cloudy water, and excess waste trapped in high-flow systems. Denison Barbs are enthusiastic feeders, so it is easy to give too much. Feed small portions twice daily rather than one heavy meal.
The Red-Line Torpedo Barb has a long, streamlined silver body with a black lateral stripe running from snout to tail and a vivid red stripe across the upper body that often extends from the nose through the eye. The tail usually shows black and yellow patterning, adding extra contrast when the fish turns in current. Adult roseline shark size and denison barb max size in aquariums is usually around 12 cm, though body depth and finnage make mature fish look especially substantial.
People searching for a "gold denison barb" are usually looking for a brighter specimen under warm lighting rather than a separate colour form. Standard Denison Barbs are silver-red-black rather than true gold, but an excellent diet and a dark background can intensify the red line beautifully.
Sexing them is not always easy. To tell a red line torpedo barb male or female apart, mature females are often slightly fuller-bodied, especially when carrying eggs, while males may appear slimmer and more streamlined. If a fish fades in colour, that usually points to stress, poor water quality, or a group that is too small rather than a sexual difference.
One of the biggest strengths of this species is its community potential. The Denison Barb is peaceful, active, and social, making it an excellent choice when you want movement without constant aggression. The key is choosing tank mates that enjoy similar water conditions, appreciate swimming room, and are not tiny enough to be intimidated. In practical terms, the best denison barb compatible fish are medium-sized, peaceful, confident species.
Good choices include rainbowfish, larger tetras, peaceful loaches, and bottom dwellers such as Corydoras in suitably sized tanks. Among barbs, you can build a lively display with companions such as the Rosy Barb or the Cherry Barb, provided the aquarium is large enough and the smaller species are not overwhelmed. Browse the full barbs collection for more group-friendly options.
Avoid very small nano fish, slow long-finned fish that dislike current, and aggressive cichlids. Mixing denison barbs with African cichlids usually ends in disappointment because the temperament and water-style mismatch is too great. Keeping denison barbs with angelfish can work in a very large, calm setup, but their active feeding behaviour may stress shy angels. Being tropical river fish, they should never be mixed with fancy goldfish, and bettas are a poor fit because of the flow and activity differences.
Large adult shrimp may survive in a mature, planted aquarium, but small shrimp and shrimplets are at risk. Snails are usually safer, though eggs or tiny juveniles may be pecked. If your main goal is a shrimp colony, choose a different community fish.
| Species | Compatible? | Notes |
|---|---|---|
| Rosy Barb | Yes | Works in large tanks with a similar temperature and active swimming style. |
| Cherry Barb | Caution | Only in spacious, well-planted aquariums; smaller fish may be overshadowed. |
| African cichlids | Avoid | Too aggressive and unsuitable in water style and behaviour. |
Always quarantine new arrivals for 2-4 weeks before adding them to a Denison Barb group. Fast shoaling fish can spread parasites quickly if a single new fish arrives with whitespot or bacterial stress.
Denison barb breeding is considered difficult in home aquariums. Unlike easier egg scatterers, this species has historically been challenging to spawn consistently outside specialist facilities. Commercial captive breeding has improved greatly, which is excellent for conservation, but hobby-level success still requires patience, space, and excellent conditioning.
Use a separate breeding tank with pristine water, strong oxygenation, and gentle but steady flow. Condition a healthy group on varied frozen foods and vegetable matter. Because sexing is subtle, keep several mature fish and watch body shape over time; females are generally rounder when viewed from above.
Spawning is thought to be triggered by excellent water quality, seasonal-style water changes, and conditioning foods. Denison Barbs are egg scatterers, and adults should be removed after spawning if eggs are found. Fine-leaved plants or spawning mops help catch eggs. Fry need tiny foods such as infusoria or powdered fry foods at first, followed by newly hatched brine shrimp. The denison barb growth rate is moderate rather than extremely fast, and juveniles need clean water and frequent small feeds.
For the best chance of success, work with a mature group in a long species-only setup and use repeated cool, soft water changes to mimic seasonal river conditions. Most failures come from trying to breed young fish in tanks that are too small or too still.
Many aquarists compare the Denison Barb with smaller, hardier barbs. This matters because the Denison Barb is larger, faster, and more demanding in terms of tank length and flow. If you want a dramatic shoal in a big aquarium, it is hard to beat. If you need something for a smaller setup, another barb may be the better fit.
| Feature | Denison Barb | Smaller Community Barbs |
|---|---|---|
| Max Size | Around 12 cm | 5-10 cm |
| Care Level | Moderate | Easy to moderate |
| Temperature | 20-25°C | 18-26°C |
| Flow Need | High | Low to moderate |
| Best For | Large river-style community tanks | Smaller active barb communities |
Choose the Denison Barb if you want the classic roseline shark size and movement that smaller barbs cannot match. Choose a smaller species such as the Rosy Barb if your aquarium is shorter, cooler, or more modestly stocked. The deciding factor is nearly always tank size: Denison Barbs reward open horizontal space more dramatically than almost any other barb.
A healthy Denison Barb is alert, streamlined, brightly marked, and constantly on the move. The red stripe should be clear, the fins held open, and the fish should school confidently with its group. Clamped fins, faded colour, hanging near the surface, or isolating from the shoal are warning signs that something is wrong.
The most common denison barb disease issues are not species-specific genetic problems but stress-related illnesses caused by poor water quality, low oxygen, shipping stress, or crowding. Whitespot, bacterial fin damage, and external parasites can all appear if fish are introduced without quarantine. Because Denison Barbs are active and social, they often show stress quickly when water quality slips.
Start with water testing and a large partial water change. Increase aeration, check filter performance, and isolate visibly ill fish where possible. Use medications carefully and always identify the problem before treating. If invertebrates are present, remember that many treatments are unsafe for them.
Never use copper-based medications in aquariums containing shrimp or other sensitive invertebrates. Copper can be lethal even at low levels, and active community tanks can spread medication exposure quickly.
Denison Barbs are active, midwater shoalers that spend much of the day cruising back and forth in coordinated bursts. They are not shy once settled, but they can be nervous in undersized groups, which is why denison barb school size is so important. In a proper group they look confident and elegant; in pairs or trios they often look restless.
They are generally peaceful, though they can become competitive at feeding time. Apparent aggression is usually really crowding, poor group structure, or food competition. Give them room, current, and a proper shoal, and they are among the most graceful active fish in the hobby. Natural behaviour is easiest to observe in a long tank with open lanes, directional flow, and a dark background.
When customers search for tropical fish for sale UK, buy tropical fish UK, buy denison barb UK, buy torpedo barb UK, buy miss kerala barb UK, denison barb online UK, or a red-line torpedo barb price UK, they are usually trying to avoid weak, stressed imports and find fish that are already feeding and stabilised. That matters even more with Denison Barbs because they are active, oxygen-demanding fish that do poorly when rushed from shipment to sale tank to home aquarium.
Our Denison Barbs are selected for clean body lines, intact fins, strong schooling behaviour, and clear red lateral striping. Before dispatch, they are observed for feeding response and general balance in the water column, which helps us avoid sending fish that have not fully recovered from transport stress. We also provide practical acclimation guidance for UK home aquariums, especially for keepers moving fish into larger river-style setups.
Each order is packed for live fish transport with insulated packaging, tracked delivery via a licensed live-animal courier, and seasonal heat protection when needed. Fish are bagged professionally to maintain temperature and oxygen during transit. If you have been searching for a denison barb for sale or a red line torpedo barb for sale, this is one of the best upgrades for a serious community tank.
If you enjoy active barb communities, consider pairing your Denison Barbs with a hardy classic such as the Rosy Barb or the colourful Cherry Barb. You can also browse the full barbs collection or our wider tropical fish for sale UK range for community species, foods, and aquarium essentials that suit fast-moving shoaling fish.
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