Bleeding Heart Tetra

Tank Setup:

The 'Blackwater Amazon' Mandate. Because they are deep-bodied, tall, and highly active, they demand long horizontal swimming space (minimum 40 inches / 100 cm or a 30-to-40-gallon breeder tank). THE FATAL LIGHT MISTAKE: They naturally inhabit dark, shaded, muddy forest streams. If you throw them into a tank with blinding LED lights, white sand, and no plants, they will suffer extreme chronic terror, permanently hide behind the filter, wash out to a dull gray, and eventually die. You MUST provide dim lighting, floating plants, and scatter dried Indian Almond Leaves (Catappa) on the dark substrate to release brown, acidic tannins (Blackwater) into the tank to make them glow ruby red.

Feeding:

The Mid-Water Micro-Carnivore. In the wild, they are voracious micropredators, eating tiny insects that fall into the river and aquatic larvae. In captivity, they are unfussy and aggressively eager eaters. While they will happily accept generic crushed flakes or slow-sinking pellets, you absolutely MUST feed them frozen or live foods (Bloodworms, Daphnia, Brine Shrimp, Tubifex) several times a week. This heavy protein diet is the strict biological requirement necessary to grow out the male's massive, trailing sickle-shaped dorsal fins.

Water Quality:

The Soft-Water Requirement. Unlike the bulletproof beginner fish (like Guppies or Zebra Danios), the Bleeding Heart Tetra is quite unforgiving of bad water. They strongly dislike hard, alkaline tap water (Liquid Rock). If forced to live in water with a high GH or pH above 7.5, their kidneys suffer, they lose their immune slime coat, become highly susceptible to Ich (White Spot) and fungal infections, and slowly waste away. They strictly demand soft, slightly acidic water (pH 5.5 - 7.0) with zero Ammonia or Nitrites. Temperature: 73°F - 82°F (23°C - 28°C).

Compatibility:

The Gentle Giant. Because of their tall, deep bodies, they are virtually impossible for most medium-sized predators (like Angelfish) to swallow whole. This makes them the ultimate, robust dither-fish for South American Cichlid tanks (Geophagus, Severums, Apistogrammas). They are incredibly peaceful towards other species and will totally ignore bottom-dwelling Corydoras and Plecos.

Reproduction:

The Expert Breeder's Nightmare. They are notoriously, frustratingly difficult to breed in a home glass box. They are egg-scatterers, but to trigger spawning, the aquarist must artificially recreate an extreme, flooded Amazonian rainy season. This requires isolating a conditioned pair in a completely dark tank, flooding it with pure, 100% Reverse Osmosis (RO) water filtered through heavy peat moss to crash the pH down to an extreme 5.5. The parents will scatter 300 eggs and immediately try to eat them all if not removed.

Risks and Diseases:

1. THE 'SMALL SCHOOL' DEATH (Solitary Confinement Terror): The biggest and most fatal beginner mistake is buying only 2 or 3 Bleeding Hearts. They are obligate, deeply social schooling animals. If kept in a tiny group, the Alpha Male will become intensely stressed and hyper-aggressive, constantly chasing and harassing the single female or weak male until they die of exhaustion. A minimum school of 8 to 12 is strictly required to distribute this aggression peacefully into beautiful, harmless 'Sparring' dances. 2. ICH VULNERABILITY (White Spot): Because they demand soft, clean water, they are usually the very first fish in a dirty tank to break out in hundreds of fatal white salt-like spots (Ichthyophthirius) if water changes are neglected.