Bloodfin Tetra Identification Guide
How to recognize the Bloodfin Tetra by its silvery body and vivid red fins.
Read the full Bloodfin Tetra encyclopedia entry →
Key identification features
- Slim, torpedo-shaped body around 4-5 cm long with a translucent silver-white sheen
- All fins (dorsal, anal, caudal, and adipose) washed in a distinct blood-red color, giving the fish its name
- A faint dusky shoulder spot just behind the gill cover, more visible in younger fish
- Large, easily visible scales that give a subtle metallic shimmer under light
- Adipose fin present, a small marker used to separate it from many similar tetras
Common look-alikes
- Serpae Tetra: has a solid black shoulder blotch and a red body wash, unlike the Bloodfin's clear/silver body with only the fins colored red.
- Redeye Tetra: shows a bright red eye but a silver body and clear fins, the opposite color pattern of the Bloodfin.
- Glowlight Tetra: has a single glowing orange-red horizontal stripe rather than red fins on a silver body.
Where you'll see one
Bloodfin Tetras come from slow-moving tributaries, streams, and backwaters of the Paraná-Paraguay river system in Argentina, Paraguay, and southern Brazil, typically schooling in open water above sandy or leaf-littered bottoms.
Frequently asked questions
How do I tell a Bloodfin Tetra from a Serpae Tetra?
Look at the body color: the Bloodfin's body stays clear silver with only the fins turning red, while the Serpae Tetra's whole body flushes red and carries a bold black shoulder blotch the Bloodfin lacks.
What is the single most reliable field mark for this species?
The combination of a silver, unmarked body with every fin (not just the tail) tinted a uniform blood-red is the most dependable identifying trait.