Bloodfin Tetra Care Guide

Introduction

Aphyocharax anisitsi, the bloodfin tetra, is a slender, silvery tetra with vivid red fins. They are notable for being one of the most cold-tolerant tetras available, capable of surviving temperatures as low as 60 degrees F, which makes them suitable for unheated aquariums in temperate rooms.

Native to the Rio Parana basin in Argentina, bloodfin tetras come from the cooler subtropical rivers of South America. Their tolerance of cool conditions and their hardiness make them excellent beginner fish.

Bloodfin tetras are easy to care for, peaceful, and adaptable. Their unique cold-tolerance expands their suitability to aquariums and environments where typical tropical fish would not thrive.

Basic Overview

Common Misconceptions

"They need tropical temperatures." Bloodfin tetras can survive temperatures as low as 60 degrees F and do well in the 65-75 degrees F range. They are one of the very few tetras suitable for unheated aquariums in temperate homes.

"They have a short lifespan like other tetras." Bloodfin tetras can live 5-7 years or more, significantly longer than many small tetra species. Their cool-water tolerance is associated with a slower metabolism and longer life.

"Red fins indicate health issues." The vivid red fin color is entirely natural and healthy. Pale or faded fin color is the disease indicator, while bright red confirms excellent health.

Recommended Setup

• 15-20+ gallon tank for a school of 8
• Planted or open community setup
• Moderate flow
• Good filtration
• No heater required in temperate rooms

Diet

Bloodfin tetras are omnivores that accept most standard foods:

• High-quality small flake or micro pellets
• Frozen bloodworms
• Frozen brine shrimp
• Frozen daphnia

Feed twice daily in small amounts. Bloodfin tetras are straightforward, non-fussy feeders. A varied diet maintains the most vivid red fin coloration.

Personality

Bloodfin tetras are lively, sociable fish that school actively and are highly visible in any tank. Their silver body and vivid red fins create a striking visual effect that is particularly dramatic in schools of 8 or more.

Their cold-tolerance makes them compatible with goldfish, white cloud mountain minnows, and other cool-water fish that cannot share a tank with typical tropical species. This unusual cross-compatibility makes bloodfin tetras unique among tetras.

They are peaceful with all community fish and do not nip fins. Their long lifespan relative to other small tetras makes them a more enduring community fish investment.

Water Parameters

Bloodfin tetras come from the cool, subtropical Rio Parana in Argentina:

• pH: 6.0-8.0 (very adaptable)
• Hardness (gH): 5-20 dGH (very adaptable)
• Temperature: 60-80 degrees F
• Ammonia and Nitrite: 0 ppm
• Nitrate: below 25 ppm

Here are some top tips to deal with unwanted parameters:

• Their exceptional temperature tolerance is the defining characteristic of this species. No heater is needed in rooms that stay above 65 degrees F.
• They are highly adaptable to water chemistry. Standard tap water in virtually any area is appropriate.
• Weekly 25% water changes are all that is needed.
• Cool temperatures (65-75 degrees F) are associated with their longer lifespan.