Should I buy it?
Serpae Tetra
Hyphessobrycon eques
Also known as: jewel tetra
A notorious fin-nipper that needs a large group to redirect aggression inward. A school of twelve in the right tank is beautiful; fewer creates a fin-shredding problem.
Serpae Tetra tank mates · 100L tank size hub
semi-aggressive · intermediate care
Sources & confidencehigh · partially verified · beginner: caution
Checked against several solid care sources that mostly agree. Numbers here are a careful starting point. Your tap water, tank size, and habits decide the rest. How we evaluate.
Best for: Species-specific tanks or planted tanks 100L or more with ten or more serpae and no long-finned companions.
Avoid if: You keep bettas, angels, guppies, or any long-finned fish. Any community tank with fewer than ten serpae.
Common mistakeThree serpae tetras in a mixed community is the classic fin-nipping setup. Small groups focus relentless attention on long-finned neighbours instead of dispersing energy inside a real school. Keep at least eight — preferably ten or more — in a longer planted tank, or skip the species. Under-stocking creates the reputation; it is not bad luck.
Top things that go wrong
- Fin-nipping risk in typical community layouts. Will nip long fins or slow fish when the school is too small, bored, or kept in a short tank.
- Group welfare — not a solo display fish. Plan at least **8** together for normal behaviour; smaller groups often mean stress, colour loss, or nipping depending on species.
- Shrimp & snails. Shrimp are a gamble with this fish; some ignore them, some clear a colony in days.
What most shops don't tell you
- 1.Serpaes are still sold into calm community lists beside neons as if red equalled gentle. The colour is real; the temperament depends on numbers and tank mates. A short tank with a betta or fancy guppy is how the myth dies in a weekend. Believe the nipping stories when the group is small — that is the common retail stocking, not the exception.
- 2.Buying three or four to start. Serpae Tetra settles in a group of 8 or more. An understocked school sulks at the back of the tank and loses colour within a fortnight.
- 3.Eight or more in a long planted tank. No guppies or bettas in the mix. Serpaes are not a safe default community fish; they nip long fins when bored.
- 4.Serpae tetras can nip long fins when understocked or bored — large schools and no long-finned tank mates.
About this species
Serpaes are red-finned tetras that nip long fins when the school is small or the tank is short. A bigger school in a long tank reduces nipping. Still a poor match for slow long-finned fish.
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No reverse lookups listed yet.
Plan grid
Key limits are above. Here: pH band, swim level, bioload, and activity.
Swim zones
Care snapshot
Quick compare before you buy. Not a score of how “good” the fish is.
- Beginner ease38
- Peacefulness30
- Community fit12
- Small-tank fit100
- Hardiness54
- Energy86
Numbers are deterministic planning indices from Fishori fields — not a scientific score of your individual fish.
Example setups
Starting points only. Run the pair checker for every fish you add.
Prioritise 8+ of Serpae Tetra in 100L+ with filtration sized for messy feeding — add only mates that already pass pair checks with this species.
Compatibility
Tank mates for Serpae Tetra
No unconditional “safe” tank mates are listed for Serpae Tetra — this shortlist has CAUTION pairings that need specific conditions and RISKY pairings to avoid. Conditional (CAUTION — read the pair page before buying): Angelfish, Bristlenose Pleco, Corydoras Catfish, Discus, Dwarf Gourami. Avoid (RISKY): Betta. Every name links to a live pair check — the lists are a shortlist, not a stocking plan.
Usually safer
Open a pair page with this fish as the starting point.
None listed. Use the pair checker before mixing.
Needs planning
Read the blocking rule on each pair page before experimenting.
Usually avoid
Do-not-stock combinations on conservative hobby rules.
No safe-mate list on this record yet. Use the fish index to find species with similar care, then run a pair check before you buy.
Behaviour and temperament
Serpae tetras nip when the school is too small, the tank is too short, or long-finned fish share the water. Eight is a common floor on charts; ten or more is when they usually spend energy on each other at feeding time instead of shredding neighbours. Semi-aggressive here means fin testing, not territory wars — damage still ruins bettas, angels, and fancy guppies. A flurry when food hits the water is normal school energy; focused chasing of one long-finned fish is the warning.
What sets them off
- Small groups or boredom
- Long-finned or slow tank mates
- Bare tanks without structure
Fin nipping: Will nip long fins or slow fish when the school is too small, bored, or kept in a short tank.
Predation: Not a predator toward similarly sized community fish; fry and dwarf shrimp are still fair game for most species.
Territory: Not strongly territorial, but still needs room so its working space does not overlap the next fish.
Planted tanks: good — easy plant ideas
In the glass: typical and warning signs
- Midwater school that colours up when numbers are high and the tank has length.
- Feeding-time flurry inside the group is normal energy, not a riot to break up.
- Persistent targeting of one long-finned fish — group too small or tank too short.
- Washed-out colour and skittish packing after parameter swings.
- Fin nipping rises hard in groups under about ten or beside slow long-finned species.
- Equal-sized robust fish usually take display better than bettas or angels.
- A shredded betta or guppy → remove the victim and rethink the serpae count.
- One serpae endlessly pinned by the school → check numbers and sight lines.
Fish behaviour can vary between individuals and tank setups. Always observe new fish closely after introduction.
Water, food, and grouping
Hardness
soft
Diet
omnivore
Serpaes are enthusiastic midwater feeders that can strip flake before quieter fish eat. Feed enough for the whole school in a short window, using flake or micro-pellets they finish quickly, plus frozen food a few times a week. Idle hunger in a tiny group is when nipping at fins replaces foraging. If only the front of the school is fat, widen the feed or add a second pinch.
Shrimp & snails
Shrimp are a gamble with this fish; some ignore them, some clear a colony in days.
Schooling species — buy 8+ together. Smaller groups stress and lose colour.
- Hold 22 to 28 °C steadily on a real thermometer, not the dial on the heater.
- Aim for pH 5 to 7.5 and a hardness you can re-test in two weeks. A one-time strip in the shop car park is not a water test.
- Schooling species. Buy 8 or more from the same tank on the same day before adding any centrepiece fish.
- Tank volume meets or exceeds 100L published minimum for adults.
- You can stock at least 8 individuals (group welfare).
- Heater can hold 22–28°C without cooking cooler-water tank mates.
- No known fin-nippers paired with long-finned fish unless you accept documented risk.
Explore and stocking hubs
Tank-mates hub, matching guides, category peers, and litre stocking lists around this species’ minimum tank.
Plan with tools
Check mates as pairs first, then add this fish in the tank builder for the full stocking.
Filtration & heating
A 100L minimum tank needs a filter rated for at least 400L/hr turnover and a heater to hold 22–28°C reliably.
Plant suggestions
Serpae Tetra does well in planted tanks. Plants compatible with 22–28°C and pH 5–7.5:
Research: partially verified · Confidence: high · 3 linked source(s). We do not invent citations.
How Fishori evaluates compatibility (same logic as pair and tank tools).
- Seriously Fish. Hyphessobrycon eques
Supports: aquarium size, water chemistry, temperament and compatibility (primary care reference).
- FishBase. Hyphessobrycon eques
Supports: taxonomy and wild maximum size — translate to tank stocking, not a target number.
- Wikipedia. Hyphessobrycon eques
Supports: general species background and common-name orientation only.
Evidence notes
- Care numbers are cross-checked across the linked sources and biased toward the conservative end; compatibility reflects typical hobby experience, not a lab prediction. Method and full source policy: /methodology.
Featured compatibility checks
Curated pair pages for Serpae Tetra. Each opens a full verdict — not just a list label.
Common questions about Serpae Tetra
- How big do Serpae Tetra get?
- Serpae Tetra adults reach about 4 cm. Shop fish look smaller; stock for the adult length.
- What size tank does Serpae Tetra need?
- 100L is the planning floor for adult swimming space and bioload. A 122L+ tank is the more comfortable long-term footprint. Length and depth matter as much as raw litres for active or territorial fish.
- Are Serpae Tetra aggressive?
- Serpae tetras nip when the school is too small, the tank is too short, or long-finned fish share the water. Eight is a common floor on charts; ten or more is when they usually spend energy on each other at feeding time instead of shredding neighbours. Semi-aggressive here means fin testing, not territory wars — damage still ruins bettas, angels, and fancy guppies. A flurry when food hits the water is normal school energy; focused chasing of one long-finned fish is the warning.
- Do Serpae Tetra need to be kept in a group?
- Schooling species — buy 8+ together. Smaller groups stress and lose colour.
- What is the most common mistake with Serpae Tetra?
- Three serpae tetras in a mixed community is the classic fin-nipping setup. Small groups focus relentless attention on long-finned neighbours instead of dispersing energy inside a real school. Keep at least eight — preferably ten or more — in a longer planted tank, or skip the species. Under-stocking creates the reputation; it is not bad luck.
- What fish can live with Serpae Tetra?
- This profile currently has no curated unconditional safe-mates shortlist for Serpae Tetra. Other species may still return GOOD in the pair checker, so check the exact pair rather than treating this shortlist as exhaustive. Angelfish, Bristlenose Pleco, Corydoras Catfish, Discus are conditional (CAUTION): workable only with the specific conditions on each pair page. Avoid Betta (RISKY). Run the pair checker for your exact water and tank size before stocking.