--- type: species title: "Bloodfin Tetra Care Guide: The Hardiest Schooling Fish for Beginners" slug: "bloodfin-tetra" category: "freshwater" scientificName: "Aphyocharax anisitsi" subcategory: "Tetra" lastUpdated: "2026-04-24" readingTime: 9 url: https://www.fishstores.org/species/bloodfin-tetra --- # Bloodfin Tetra Care Guide: The Hardiest Schooling Fish for Beginners *Aphyocharax anisitsi* Learn how to care for the Bloodfin Tetra (Aphyocharax anisitsi). Discover ideal tank mates, water parameters, and why these silver-and-red fish live up to 10 years. ## Species Overview Bloodfin tetras (*Aphyocharax anisitsi*) are slim, silver-bodied schooling fish from the Parana River basin in northern Argentina, Paraguay, and southern Brazil. The name comes from the deep blood-red wash that floods the dorsal, caudal, anal, and pelvic fins of healthy adults — the contrast against a polished silver flank is unmistakable in a planted tank. They have been a community-aquarium staple in the United States since the 1950s, valued less for spectacle than for the qualities that actually matter long term: they are nearly bulletproof, they shoal hard, and they outlive almost every other small tetra in the hobby. If you want a hardy, attractive, active schooling fish that can survive a beginner's mistakes and still be in your tank a decade later, this is the species. They handle cooler water than most tropicals, eat anything you offer, and tolerate the kind of parameter ranges that would stress out a cardinal tetra in a week. | Field | Value | | ----------- | -------------------------- | | Adult size | 2 in (5 cm) | | Lifespan | 5-10 years | | Min tank | 20 gallons (school of 6+) | | Temperament | Peaceful, active schooling | | Difficulty | Beginner | | Diet | Omnivore (surface feeder) | ### Origin: The Parana River Basin *Aphyocharax anisitsi* is native to the warm, slow-moving tributaries of the Parana River system that drain through northern Argentina, Paraguay, Uruguay, and parts of southern Brazil. The defining feature of this watershed is its seasonal temperature swing — water can sit in the high 70s during the wet austral summer and drop into the low 60s during cooler months. That climatic reality is what makes bloodfins so much more cold-tolerant than tetras from the Amazon proper, and it is the reason they thrive in temperate-climate aquariums that other tropicals cannot handle. In the wild they school in open water near the surface, picking off insects, larvae, and small crustaceans drifting on or just below the meniscus. They are not blackwater fish — they prefer slightly harder, more neutral water than their Amazonian cousins. ### Appearance: Silver Bodies and Striking Red Fins The body is elongated, laterally compressed, and a clean reflective silver that takes on a faint olive-blue sheen along the dorsal ridge under good light. The signature feature is the saturated red-orange wash on the unpaired fins (dorsal, caudal, anal) and the pelvic fins — the pectorals stay clear. In poorly conditioned or stressed fish the red fades to pink or pale orange, which is one of the easiest health indicators to read in a store tank. Sexual dimorphism is subtle. Females are slightly larger and rounder in the abdomen; mature males develop tiny hooks on the anal fin rays that catch on a fine net during handling. Bloodfins are sometimes confused with the closely related glass bloodfin tetra (*Prionobrama filigera*), which has a more transparent body, a longer lower caudal lobe, and a slimmer overall profile. ### Lifespan: Why They Outlast Most Other Tetras Most small tetras live 3-5 years. Bloodfins routinely live 5-8 years and there are well-documented hobbyist reports of individuals reaching 10. The longevity comes from a combination of factors — they are larger and more robust than micro-tetras like ember or chili, they evolved in a variable-temperature environment that built tolerance for swings, and they have a stronger immune profile than the more delicate Amazonian species. That long lifespan has a downstream consequence at the LFS: bloodfins frequently sit in store tanks for months without selling. A school you buy could be six months or six years old. Active behavior and saturated red fins are the diagnostic for young, healthy stock. ## Water Parameters & Tank Requirements Bloodfins are forgiving on chemistry but unforgiving on swimming space. Get the tank size and stability right and the rest is mostly hands-off. ### Temperature Range: The Sub-Tropical Advantage (64-82°F) Bloodfin tetras tolerate a temperature range from 64°F to 82°F (18-28°C), which is wider than almost any other commonly-kept tetra. The sweet spot for daily life is a stable 72-78°F. They are one of the few tropical species that genuinely thrive in unheated indoor tanks in temperate climates — if your home stays above 65°F year round, you can run their tank without a heater entirely. That said, stability matters more than the absolute number. A tank that bounces between 68°F and 78°F over 24 hours is harder on them than one that sits at a steady 70°F. If you are running unheated, place the tank away from drafty windows and exterior walls. > **Cool-water tolerant — one of the few true unheated-tank tetras** > > Bloodfin tetras tolerate temperatures down to 64°F (18°C), which makes them one of the very few tropical schooling fish suitable for unheated indoor aquariums. If you live somewhere your house stays above the mid-60s year round, you can skip the heater entirely. They also pair well with white cloud mountain minnows, hillstream loaches, and other cool-water species in the lower end of the tropical range — pairings that are off-limits to warm-only tetras like cardinals or rummy-nose. ### pH and Hardness: 6.0-8.0 pH and 5-20 dGH Aim for a pH between 6.0 and 8.0, with 6.5-7.5 ideal. Hardness should fall between 5 and 20 dGH. Unlike soft-water Amazonian tetras, bloodfins do well in moderately hard tap water and are unbothered by neutral-to-slightly-alkaline conditions. There is no reason to mix RO water for this species unless your tap is genuinely extreme. Cycle the tank fully — zero ammonia, zero nitrite, measurable nitrate — before adding any livestock. A fish-in cycle is unnecessary with this species' resilience and still produces avoidable losses. ### Minimum Tank Size: Why 20 Gallons Is the True Baseline The 10-gallon stocking advice you will see on outdated care sheets does not match how this species actually behaves. Bloodfins are extremely active swimmers that constantly cruise the upper third of the water column at speed. A school of six in a 10-gallon tank looks cramped within a day, and the fish develop nipping behavior toward each other and any tank mate within reach. A 20-gallon long is the practical minimum. The longer footprint matters more than raw volume — they need horizontal swimming distance, not vertical depth. For a school of 8-10 with a few mid-water companions, a 29-gallon or 30-gallon long is ideal. Build the tank with open swimming space across the front and middle, then plant the back and sides for cover. See our [20-gallon fish tank guide](/guides/20-gallon-fish-tank) for stocking and equipment recommendations that fit a bloodfin community. ### Filtration: Managing High Activity and Oxygenation Bloodfins do well with a standard hang-on-back filter on a 20-30 gallon tank, sized for the actual gallonage. Their oxygen demand is higher than most tetras because of their constant swimming — make sure the filter return creates surface agitation, or add a small air stone for redundancy. They handle moderate flow comfortably and will play in the current near a powerhead outlet, which is a behavior you almost never see from soft-water Amazonian species. A tight-fitting lid is non-negotiable. Bloodfins are jumpers — they leap when startled and during spawning. An open-top tank will lose fish. ## Diet & Feeding Bloodfin tetras are surface-oriented omnivores that accept virtually any prepared or live food sized to fit their mouth. Feeding them is the easiest part of their care. ### High-Quality Flakes and Micropellets A quality flake or small pellet formulated for tropical community fish forms the daily staple. Look for products with whole-fish protein in the first ingredient and added carotenoids — astaxanthin in particular intensifies the red fin coloration over time. Standard brand options like Hikari Micro Pellets, Bug Bites Tropical, Omega One Color, and Tetra Color Bits all work well. Crush large flakes lightly so the pieces drift slowly across the surface where the fish naturally feed. Feed twice daily, only what the school can clear in 2-3 minutes. Their upturned mouth morphology means food sinking past the mid-water column is largely wasted — match portion size to surface feeding behavior. ### Frozen and Live Foods Supplement the dry-food base 2-3 times per week with frozen or live items. Brine shrimp (frozen or live), daphnia, and bloodworms are all excellent. Daphnia in particular triggers visible hunting behavior across the upper water column and serves as a natural laxative that keeps digestion moving. Live blackworms or chopped earthworms are a strong conditioning food if you intend to breed. For a planted-tank community, a varied rotation of dry plus frozen produces noticeably better color than a flake-only diet within 4-6 weeks. ### Surface Feeding Habits Bloodfins have a slightly upturned mouth designed to pick prey from the water surface. They will dart down for sinking food but their natural feeding zone is the top inch of the tank. This makes them poor competitors for slow bottom-dwellers like corydoras, which is actually a feature rather than a bug — the bottom feeders get their share without the bloodfins stealing it. ## Tank Mates & Compatibility Bloodfins are peaceful when kept properly and semi-aggressive when not. The single biggest variable is school size. ### The Rule of 6: Why Schooling Size Prevents Fin-Nipping A bloodfin tetra in a school of 3 or 4 is a different fish from one in a school of 8 or more. Below the threshold, the school feels insecure and individuals begin nipping at each other and at any long-finned tank mate within reach. Above the threshold, the social dynamics stay internal to the school and other species are left alone. Six is the absolute minimum, eight is better, and ten or more produces the best behavior and the most striking visual display. > **A school of 6 is the minimum — 8-10 is the visual sweet spot** > > Bloodfin tetras are obligate schoolers. A group of 6 is the floor; below that they show stress behavior, faded color, and elevated fin-nipping. A school of 8-10 in a 20-30 gallon tank is where the species really shows off — synchronized swimming across the upper water column, deeper red fin saturation, and zero aggression toward tank mates. Buy more than you think you need. The single best upgrade you can make to a struggling bloodfin tank is adding 4-6 more bloodfins. ### Best Community Partners Excellent tank mates include corydoras catfish (any species — bronze, panda, julii, sterbai), [neon tetras](/species/neon-tetra) and other peaceful tetras, harlequin rasboras, peaceful barbs (cherry barbs, gold barbs), zebra danios, white cloud mountain minnows, and small loaches. The corydoras pairing is particularly clean because the bottom-dwellers and the surface-feeding bloodfins occupy completely different zones. [Ember tetras](/species/ember-tetra) work in larger tanks (20+ gallons) where the size difference does not become a feeding-time issue, and the warm-orange embers make a great color contrast with the silver-and-red bloodfins. Both schools should be kept at full size (8+ each) so neither feels outnumbered. ### Species to Avoid: Long-Finned and Slow-Moving Fish > **Fin-nipper risk with long-finned species — avoid bettas and angelfish** > > Bloodfin tetras have a documented tendency to nip the trailing fins of slow-moving, long-finned tank mates. Never house them with bettas, angelfish, fancy guppies, fancy goldfish, or any veiltail variety. Even in a properly-sized school of 8+, the temptation of a slow-drifting flowing fin is too much for them to resist. The damage is usually gradual — frayed edges, then full-tail tears, then stress and infection in the target fish. There is no fix short of separating the species; pick tank mates with short fins from the start. Avoid keeping with bettas, angelfish, fancy guppies, fancy goldfish, and any other long-finned, slow-moving species. Also avoid large aggressive fish that view bloodfins as food — adult cichlids, large gouramis, and predatory catfish. ## Breeding the Bloodfin Tetra Bloodfins spawn readily in soft, slightly acidic water with a temperature bump and a little patience. They are egg scatterers with no parental care. ### Distinguishing Males vs. Females Mature females are slightly larger and noticeably rounder in the belly, especially when carrying eggs. Males are slimmer and develop tiny bony hooks on the anal fin rays (a defining feature of the *Aphyocharax* genus) that you can feel if you handle the fish — these hooks notoriously catch on fine breeding nets, so transfer males with a glass cup rather than a net. Color is not a reliable sex indicator. Both sexes show the red fin wash equally. ### The Spawning Leap: Why a Tight-Fitting Lid Is Mandatory Bloodfins are jumpers in normal conditions and become extreme jumpers during courtship and spawning. The male chases the female across the tank and both fish leap several inches above the water surface during the spawning embrace. An open-top tank or one with significant lid gaps will lose fish — this is not theoretical, it is the most common cause of bloodfin death in the home aquarium. Use a glass canopy with the cutouts sealed off, or run a tight-fitting acrylic lid with no openings larger than half an inch. The same advice applies year-round, not just during breeding. ### Raising Fry: Infusoria and Baby Brine Shrimp To breed, condition a group of 2 males to 4 females for a week on live and frozen foods, then move them to a separate breeding tank with soft, slightly acidic water (pH 6.0-6.8, sub-5 dGH), a temperature of 78-80°F, and a layer of marbles or fine spawning mops on the bottom to protect eggs from being eaten by the parents. Spawn happens at first light. Remove the adults immediately after. Eggs hatch in 24-30 hours and fry are free-swimming after 4-5 days. Start fry on infusoria or commercial liquid fry food for the first week, then transition to baby brine shrimp once they can take it. Grow-out takes 2-3 months to reach saleable size. ## Common Health Issues Bloodfins are hardier than most small characins, but two diseases come up routinely with this species. ### Ich (White Spot Disease) and Temperature Fluctuations Ich (*Ichthyophthirius multifiliis*) is the most common disease in bloodfin tanks and is almost always triggered by a temperature swing — a cold-water change, a heater failure, or a draft hitting an unheated tank. Symptoms are the classic white salt-grain spots on body and fins. Treat by raising the temperature gradually to 82°F and using a standard ich medication at full dose. Bloodfins handle ich treatments better than most small tetras and copper-based meds at standard doses are tolerated. Prevention is straightforward: keep temperature stable, match new water to tank temperature during water changes, and quarantine new fish for 2-3 weeks before adding to the main tank. ### Fin Rot Prevention in Active Schools Bacterial fin rot shows up as frayed, ragged, or whitening fin edges and is almost always a water quality issue, not a primary infection. In a properly cycled tank with weekly 20-25% water changes, fin rot is rare. When it does occur, the first move is a water test — ammonia or nitrite above zero, or nitrate above 40 ppm, is usually the trigger. Resolve the chemistry and most early-stage fin rot heals on its own. Persistent or advanced cases respond to broad-spectrum antibacterial treatments like Furan-2. In a too-small school, fin damage can also come from sibling nipping rather than disease. Adding more fish to the school usually resolves it. ## Where to Buy & What to Look For Bloodfins are widely stocked at chain pet stores and serious local fish stores. The challenge with this species is that they sit in retail tanks for months — sometimes years — without selling. Your goal is to identify young, healthy stock rather than long-shelved adults. > **Buy Local** > > Always inspect bloodfin tetras in person at a local fish store before buying. Look for active schooling behavior in the upper water column, vivid red coloration in the fins (not pale pink or washed-out orange), and intact, unfrayed fins. Avoid stores where the bloodfin tank shows hanging or listless fish — this species is normally one of the most active in any community display, and inactivity is a strong red flag. ### Identifying Vibrant Red Coloration in LFS Tanks Healthy young bloodfins show a saturated, almost crimson red on the dorsal, anal, caudal, and pelvic fins. The contrast against the silver body should be sharp and obvious from across the room. Faded pink or pale-orange fins indicate either old stock, poor diet, or chronic stress — any of which translates to a fish that may not adapt well to your tank. Body condition matters too. The silver flank should be reflective and bright; a dull, gray, or yellowed body suggests prolonged poor conditions. Mature adults will show slightly less saturated color than juveniles even in perfect health, but the difference between a healthy 1-year-old and a stressed 4-year-old is dramatic and visible. ### Signs of Stress: Clamped Fins and Pale Bodies Avoid any school showing clamped fins (held tight against the body rather than spread), hanging at the surface, gulping at the air, or scattered behavior with individuals isolated from the group. Bloodfins are obligate schoolers — a healthy store tank shows the entire group moving together as a unit. Loose, scattered behavior usually means recent stress or active disease. Buy at least 6, ideally 8-10, in a single trip. Adding small batches over time disrupts the established school dynamics and reintroduces fin-nipping risk. ### LFS Buying Checklist for Bloodfin Tetras - [ ] School is shoaling tightly in the upper water column — not scattered, not hiding - [ ] Fins show vivid red-orange coloration, not faded pink or washed-out orange - [ ] Silver body is bright and reflective, not dull or yellowed - [ ] Fins are erect and intact — no clamped fins, no fraying or tears - [ ] Active swimming with quick darting motions across the front of the tank - [ ] Eyes are clear with no cloudiness, swelling, or popped appearance - [ ] No white spots, fungal patches, or visible parasites on body or fins - [ ] Buy at least 6, ideally 8-10, to seed a healthy school For broader community-tank stocking guidance, see our [freshwater fish guide](/guides/freshwater-fish), which covers compatibility logic and beginner-appropriate species selection in more depth. ## Quick Reference - **Adult size:** 2 in (5 cm) - **Lifespan:** 5-8 years typical; 10 years documented - **Tank size:** 20 gallons minimum (long footprint preferred); 29-30 gallons ideal - **Group size:** 6 minimum, 8-10 ideal - **Temperature:** 64-82°F (18-28°C); sweet spot 72-78°F - **pH:** 6.0-8.0 (optimal 6.5-7.5) - **Hardness:** 5-20 dGH - **Filtration:** Standard HOB sized to tank, with surface agitation - **Diet:** Quality flake or micropellet daily; frozen/live brine shrimp, daphnia, bloodworms 2-3x weekly - **Feeding zone:** Surface and upper water column - **Best tank mates:** Corydoras, neon tetras, harlequin rasboras, cherry barbs, zebra danios, white cloud minnows - **Avoid:** Bettas, angelfish, fancy guppies, fancy goldfish, large cichlids, predatory catfish - **Difficulty:** Beginner - **Lid:** Tight-fitting required — bloodfins are notorious jumpers - **Heater:** Optional in stable indoor temperate climates above 65°F ## Frequently Asked Questions ### How many bloodfin tetras should be kept together? Keep a minimum of 6 to 8 bloodfin tetras together. They are highly social schooling fish, and smaller groups often lead to stress, shyness, and occasional fin-nipping toward tank mates as the school lacks the security of a full group. ### Are bloodfin tetras fin nippers? They can be semi-aggressive nippers if kept in a tank that is too small or in a school that is too small. In a proper 20-gallon-plus tank with 8 or more individuals, they generally keep their play behavior within the school and leave other species alone. ### Do bloodfin tetras need a heater? While they are very hardy and can tolerate temperatures as low as 64°F, they thrive best with a stable 72-76°F. They are excellent candidates for unheated indoor tanks in temperate climates where room temperature stays above the mid-60s year round. ### How big do bloodfin tetras get? Bloodfin tetras typically reach a maximum size of 2 inches (5 cm). Despite their small size, they are extremely active swimmers and need more horizontal swimming space than slower fish of the same size. ### How long do bloodfin tetras live? With proper care and stable water parameters, bloodfin tetras are exceptionally long-lived for small characins, often reaching 5 to 8 years, with some hobbyists reporting lifespans of up to 10 years. --- *Source: [FishStores.org](https://www.fishstores.org/species/bloodfin-tetra)* *Last updated: April 24, 2026*