Bloodfin Tetra
Aphyocharax anisitsi
Min Tank Size
75L
Adult Size
5.5 cm
Lifespan
10 years
School Size
6+
About
Native to the Parana River basin in South America, bloodfin tetras have been a staple of the hobby for decades, and for good reason. They carry a slim, silver body with a subtle iridescent sheen, and those fins, vivid red on the tail, anal, and pelvic fins, make them genuinely eye-catching under good lighting. Not flashy in a garish way, just clean and striking.
What sets them apart from most tetras is their toughness. They can handle temperatures as low as 18C, which means they're one of the few tropical fish that can work in unheated tanks during warmer months in temperate climates. Their pH tolerance is similarly wide, from neutral tap water to slightly acidic or even mildly alkaline conditions. New fishkeepers often gravitate toward neons or cardinals, but bloodfins will outlive both by years. A decade in captivity isn't unusual with decent care.
Feeding is simple. They'll readily take quality flake food, micro pellets, and frozen foods like daphnia or bloodworms. Variety helps keep their color vivid.
Temperament-wise, they're genuinely peaceful with no fin-nipping tendencies, which makes them reliable in mixed community tanks. They swim actively through the mid and upper column, constantly on the move without being erratic.
You'll want at least six, ideally more, to see their natural schooling behavior. A single specimen or small group will often look washed out and nervous. In a proper school they shoal tightly, especially when other tank activity picks up. If you want to see how they look in actual setups, check out community tank builds featuring this species.
Water Parameters
Temperature
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GH
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Flow Preference
Keeping multiple Bloodfin Tetra together
Bloodfin Tetra are shoaling fish and need company of their own kind. Keep a group of at least 6. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
These are genuinely flexible community fish. They do well with other peaceful tetras, rasboras, corydoras, plecos, gouramis, and livebearers like platies or mollies. Avoid pairing them with slow-moving, long-finned species like bettas or fancy guppies since the bloodfins' constant movement can stress those fish, even without direct nipping. Large or semi-aggressive cichlids are a bad fit. Dwarf cichlids like apistogrammas can work in larger tanks with plenty of cover. Avoid housing with very small shrimp species since there's a real risk of juveniles being eaten, though adults tend to be ignored.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The most common mistake is keeping too few. A group of three bloodfins will look skittish and pale compared to a school of eight actively moving together. Beyond that, they're forgiving, but don't underestimate their jumping ability. A gap in the lid is all they need to end up on the floor. Water quality matters less than with delicate tetras, but consistent parameters still beat swinging between extremes. Feed variety instead of just flake and you'll see noticeably better color. These fish reward minimal fuss with long, healthy lives.
Behavior & Aggression
Bloodfin tetras are about as peaceful as community fish get. There's no real aggression toward tankmates, no fin-nipping tendency, and no territorial posturing even at feeding time. Occasionally males will display to each other with a bit of flaring, but it rarely escalates into anything worth worrying about. The only behavioral issue beginners notice is chasing within the school itself, which is normal social hierarchy stuff and not actual aggression. Keep the school large enough and it stays organized rather than chaotic.
Things to Know
- Strong jumpers, a tight-fitting lid is essential.
- May pick at very small shrimp or shrimplets, but generally ignores adults.
- Very active swimmers, may stress slow-moving fish.
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