Serpae Tetra

1) Where they come from

Serpae tetras (Hyphessobrycon eques) come from South America—think warm, slow-ish streams and backwaters with tannin-stained water, leaf litter, and lots of plants along the edges. In the aquarium they’re not picky, but that “soft, leafy, planted” vibe really matches their personality.

2) Setting up their tank

These guys look small, but they act like they own the place. I’ve had the best results giving them space to school and a bunch of visual breaks so they can duck in and out of plants instead of taking their attitude out on tankmates.

• Tank size: 20 gallons long is a sweet spot for a proper group. You can do smaller, but you’ll see more bickering and fin nipping.
• Group size: 8–12+ if you can. The bigger the group, the less they single anyone out.
• Filtration: normal community filtration is fine; they like clean water but not a washing machine current.
• Scape: plants (real or fake), driftwood, and a few open lanes for swimming. Floating plants help calm them down too.
• Substrate: anything works, but darker substrate makes their red color pop.

Water-wise, they’re beginner-friendly. Aim for stable, not perfect. Somewhere around 72–79°F (22–26°C), pH roughly 6.0–7.5, and keep ammonia/nitrite at zero with reasonable nitrates. Regular weekly water changes keep them brighter and less snappy.

3) What to feed them

Serpaes are enthusiastic eaters. If food hits the water, they’ll act like it’s the last meal on earth. That’s great for you—easy to feed—but watch that shyer fish aren’t getting bullied away from dinner.

• Staple: a decent flake or small pellet (they’ll take either).
• Color/condition boosters: frozen or live brine shrimp, daphnia, cyclops.
• Protein treat: bloodworms now and then (don’t overdo it—rich foods can bloat them).
• Plant matter: they’re not algae eaters, but a little spirulina flake in the rotation doesn’t hurt.

4) Behavior and tankmates

They’re a classic “pretty but spicy” tetra. In a good-sized group they’re busy, fun to watch, and mostly keep it among themselves. In a small group (or cramped tank) they can turn into fin-nipping machines.

• Best tankmates: other quick, confident community fish—danios, rasboras, larger tetras that aren’t delicate, Corydoras, bristlenose plecos.
• Use caution: long-finned fish (bettas, fancy guppies, angelfish) and slow movers. Serpaes are tempted by flowing fins.
• Also watch: very timid fish that won’t compete at feeding time.

5) Breeding tips (if you want to try it)

Breeding them is doable at home, and it’s kind of fun because the adults look innocent… right up until they eat the eggs. You’ll want a separate breeding setup if you actually want fry.

• Breeding tank: 10 gallons is plenty, with a sponge filter and gentle air.
• Spawning media: a thick clump of java moss, spawning mop, or a mesh/egg grate so eggs fall out of reach.
• Conditioning: feed heavy on frozen/live foods for a week or two.
• The spawn: usually early morning. Pull the adults after you see eggs or after a day.
• Eggs/fry: dim lighting helps; fry take tiny foods first (infusoria/liquid fry food), then baby brine shrimp.

6) Common problems to watch for

Most serpae “issues” are really setup issues: too few fish, too little space, or the wrong roommates. Get the social dynamics right and they’re pretty forgiving.

• Fin nipping: almost always from small group sizes, cramped tanks, or long-finned tankmates.
• Stress fading (washed-out color): often from bright bare tanks, no cover, or unstable water. Add plants/wood and keep up with water changes.
• Ich and other common parasites: they can catch it like any community fish—quarantine new arrivals if you can.
• Bloat/constipation: usually from overfeeding rich foods (especially bloodworms). Mix in daphnia and keep portions small.
• Skipping food: unusual for serpaes—if they stop eating, check water parameters first.