Serpae Tetra
Hyphessobrycon eques
Min Tank Size
75L
Adult Size
4.5 cm
Lifespan
5 years
School Size
8+
About
Native to the river basins of South America, particularly the Paraguay and Guapore river systems in Brazil and Argentina, Serpae Tetras have been a staple of the hobby for decades. Their appeal is immediate: a rich blood-red body, a small black comma-shaped spot just behind the gill plate, and dorsal fins edged in black and white that catch the light beautifully in a well-lit tank. They're a striking fish, and a school of them moving through a planted setup looks genuinely impressive.
Water conditions are forgiving by tetra standards. They do best in soft, slightly acidic water that mirrors their blackwater origins, but they're adaptable enough to thrive across a fairly wide pH range from 5.5 to 7.5. Temperatures anywhere between 22 and 28 degrees Celsius suit them fine. They appreciate tannins and subdued lighting if you want to see their best coloration, though they'll manage in brighter tanks too.
Feeding is simple. They'll accept virtually any small food, from quality flake and micro pellets to frozen or live bloodworms, daphnia, and brine shrimp. Variety keeps them healthy and their reds looking vivid.
What most people learn the hard way is that Serpae Tetras are habitual fin nippers. This isn't occasional stress behavior, it's just what they do, especially toward anything with flowing fins or that moves slowly enough to be a tempting target. Kept in a large school in the right community, they're a bold and dynamic centerpiece fish. Browse actual tank builds with this species to see how experienced hobbyists handle the compatibility side of things.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Serpae Tetra together
Serpae Tetra are shoaling fish and need company of their own kind. Keep a group of at least 8. Smaller groups leave them stressed, washed-out in color, and prone to hiding.
Compatibility
Serpaes work best alongside fast-moving, short-finned fish that can hold their own. Good matches include tiger barbs (though that's a bold combination), robust tetras like Buenos Aires tetras or black skirts, danios, and similarly active community fish. Bottom dwellers like corydoras and plecos are generally ignored. Avoid anything with long fins, bettas, angelfish, discus, fancy guppies, or any slow-swimming species. Dwarf shrimp will be eaten or harassed constantly. Snails and larger invertebrates are usually left alone. In a 75-liter or larger tank with the right company, they thrive without causing constant problems.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The biggest mistake beginners make is keeping too few of them. Groups under six tend to direct their energy outward and become a genuine problem fish. Eight is a workable minimum, ten or more is better. The second mistake is pairing them with visually tempting tank mates out of optimism. Fin damage from Serpaes is fast, often appearing overnight, and stressed fish quickly become sick fish. They eat readily, adapt to a range of water conditions, and don't require specialized care, but their compatibility limitations mean tank planning matters a lot before you buy them.
Behavior & Aggression
Serpae Tetras are among the more reliably nippy tetras in the hobby. Unlike species where nipping is stress-triggered or a result of poor grouping, these fish will harass long-finned tank mates regardless of group size or tank conditions. Aggression typically manifests as chasing and fin shredding, targeting slow, ornate fish. Larger schools of 10 or more do redirect some attention inward, reducing pressure on other species, but it doesn't eliminate the behavior. Angelfish, bettas, gouramis, and fancy guppies are frequent victims.
Things to Know
- Confirmed fin nippers, avoid long-finned or slow tankmates
- Keep in groups of 8+ to help redirect aggression inward
- Will prey on dwarf shrimp, including adults
Community Sightings
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