Heteroctenus junceus
Blue Scorpion: Advanced Care Guide
Keeper Snapshot: A Cuban rock-and-bark scorpion that climbs readily and can stridulate when disturbed. Published secondary accounts describe comparatively low venom severity, frequent Cuban stings, and no toxin-attributed fatalities while noting suspected allergic fatalities; the underlying LD50 experiment and surveillance records were not retrieved. Big Z's keeps a no-contact boundary anyway. Give it flat cover, vertical cork, lightly damp moisture-retentive substrate, cross-ventilation, and a secure lid. This batch is 0.25-0.5 in: small juveniles/scorplings, exact instar unknown, housed one per enclosure. - Big Z
Group: ScorpionsDifficulty: Spice 3: IntermediateSetup: Lapidicolous Caribbean buthid setup: flat cover objects and vertical cork over lightly damp substrateHandling: No contact. Catch cup and long tongs only.
Use This Guide Safely
- Confirm the exact animal. Match this guide to the species, locality, size, and life stage on your label. If the ID is uncertain, use the more conservative part of the range and ask before changing the setup.
- Change one thing at a time. Treat temperature and humidity as target zones, then watch posture, burrowing, drinking, feeding, and molt behavior before making another adjustment.
- Respect the handling boundary. If the guide says no handling, fast, defensive, or medically significant, plan transfers with catch cups, locked lids, and no bare hands. For serious bites, stings, or symptoms, seek emergency medical care.
Quick Snapshot
| Temperature | No captive optimum is established. One adult LABIOFAM colony was maintained at 22.8 C (73 F), while a Cuban dry-forest source gives a regional annual mean near 25 C (77 F). A 73-80/82 F working band is a Big Z house synthesis, not a source intersection or proven optimum. Maintain a gradient and avoid uncontrolled heat. |
|---|---|
| Humidity | The LABIOFAM adult colony reported 76% RH. No validated lower threshold was found. Keep the substrate lightly damp through its depth without free water, allow exposed surfaces to become less wet, and cross-ventilate. Add water to one end of the substrate rather than spraying the animal; this physical method is Big Z house practice. |
| Setup Type | Lapidicolous Caribbean buthid setup: flat cover objects and vertical cork over lightly damp substrate |
| Substrate | Use packed, moisture-retentive coco, peat, topsoil, or a stable blend. Exact mix and depth are Big Z house choices for moisture buffering, not species measurements. Primary records place this species in rock crevices, under stones and logs, and behind bark, so provide flat cover objects and a vertical cork slab rather than treating it as a deep burrower. Centruroides gracilis is used only as a same-family Caribbean keeper analogue, not a congener. |
| Feeding | Adults in the species-level LABIOFAM colony were fed weekly. For small juveniles, very small or pre-killed prey once weekly is a same-family keeper analogue and Big Z starting practice, not H. junceus rearing evidence. Adjust from intake and condition; remove leftovers promptly and remove live prey during molt. |
| Care Difficulty | Spice 3: Intermediate |
| Handling | No contact. Catch cup and long tongs only. |
Humidity zones: Very Low under 30% - Low 30-60% - Low-Moderate 40-70% - Moderate 60-80% - Moderate-High 70-85% - High 80%+ - Very High 90%+
Enclosure Format / Size Class
- Small juvenile/scorpling (0.25-0.5 in as supplied): exact instar unknown; individual escape-proof enclosure, lightly damp substrate, flat cover, and water delivered without a drowning hazard
- Juvenile: individual enclosure with vertical cork, flat cover, moisture reserve, and a safely sized open water dish
- Adult (54-107 mm total length in revised museum material): secure individual enclosure with vertical cork, flat cover, open water, and a firmly latched lid
Warnings First
- Published secondary accounts report an LD50 around 8 mg/kg, frequent Cuban stings, and no toxin-attributed fatalities while noting suspected allergic fatalities; the underlying LD50 experiment and national surveillance records were not retrieved. Big Z's still uses no hand contact. Anaphylaxis is a general emergency possibility, not an individual prognosis.
- Scorpion-venom products have not been shown to treat human cancer. A 2017 preclinical study of Vidatox 30CH found increased hepatocellular-carcinoma cell proliferation and invasion and increased nodules in a rat model; it did not test human treatment outcomes.
- This species climbs. This batch is only 0.25-0.5 in and its exact instar is unknown, so lid and vent sizing are primary containment controls.
- House singly. Individual cages are documented in a species-level adult colony; communal outcomes in keeper reports conflict, so individual housing is the conservative rule.
- Avoid an open water hazard for very small stock. Use controlled substrate watering or another low-risk method until an open dish can be safely sized.
- Audible stridulation when disturbed is reported by a professional secondary source as defensive behavior.
Simple Care
- House one animal per enclosure.
- Build for documented rock-and-bark use: flat cover and vertical cork rather than a deep-burrow-only setup.
- Keep a moisture reserve below or to one side while exposed surfaces become less wet; never leave free water in the substrate.
- Use 73-80/82 F as a house starting band, not a published optimum.
- For very small stock, deliver water through substrate or another low-drowning-risk method; add an open dish only when safely sized.
- Adults were maintained on weekly feeding in one species colony; small-juvenile cadence is house/same-family practice.
- Latch the lid and keep every vent opening smaller than the animal's metasoma.
- Stage a catch cup before opening. No hand contact at any size.
Advanced Keeper Notes
Enclosure & Microclimate
- Primary revision records place H. junceus in rock crevices, under stones or logs, and behind bark. Provide horizontal cover and vertical cork; exact substrate depth is a house construction choice for moisture buffering.
- A Centruroides gracilis care sheet is a same-family Caribbean keeper analogue only. It is a different genus and does not establish H. junceus depth, ventilation, juvenile feeding, or life-stage requirements.
- No species ventilation specification was found. Use effective escape-proof cross-ventilation as Big Z house practice, with every opening smaller than the smallest animal's metasoma.
- The LABIOFAM adult colony reported 76% RH. That observation is not a threshold or optimum; physical moisture cues and ventilation are the operating controls.
- Individual housing is supported by species-colony practice and conservative loss prevention. Conflicting communal anecdotes do not justify exposing stock to cannibalism risk.
Feeding, Growth & Maintenance
- A species-level adult LABIOFAM colony fed once weekly. This is a maintenance observation, not a tested optimum and not a small-juvenile outcome study.
- No H. junceus scorpling schedule was verified. Very small or pre-killed prey once weekly is a same-family keeper analogue and Big Z starting practice; record intake and condition and adjust.
- Supplier length does not establish instar. The prior 1st-2nd instar ladder was not reproducible on re-fetch and is not used.
Possible Origin / Range
- Likely native range: Cuban endemic. Esposito et al. 2017 record it across the island and on several offshore islets in fourteen provinces - Camaguey, Cienfuegos, Ciego de Avila, Granma, Guantanamo, Havana, Holguin, Isla de la Juventud, Las Tunas, Matanzas, Pinar del Rio, Santiago de Cuba, Sancti Spiritus and Villa Clara - at elevations from 55 to 716 m. Older sources listing Haiti, the Dominican Republic, Venezuela or Central America predate that revision, when Rhopalurus junceus was a catch-all; Hispaniolan animals are other Heteroctenus species. The supplier did not provide a locality for these animals, so no finer claim is made.
- Habitat translation: Cuban dry and semideciduous forest on karst limestone, averaging about 25C and 1,000-2,000 mm of rain a year, where the animal lives under stones and logs and behind tree bark. Translated to a build: warm ordinary room temperature, a lightly damp substrate that never sits wet, flat cover objects and a vertical cork slab as the actual retreats, cross ventilation, and a secure lid. This is a labelled synthesis of the primary microhabitat record, regional ecoregion climate, one species-level adult laboratory colony, and Big Z's house standards - not a measured captive optimum.
Advanced Keeper Details
- Most older literature uses Rhopalurus junceus. Esposito et al. (2017) revalidated Heteroctenus for the Greater Antillean group, and current Cuban work uses the new combination.
- Esposito et al. (2017) and Prendini (2026) treat Rhopalurus melloleitaoi and R. aridicola as junior synonyms of H. junceus. The current Scorpion Files instead recognizes H. melloleitaoi and H. aridicola as valid species. This is an unresolved catalogue conflict, so neither name is a commercial match alias.
- Revised museum material gives 54-107 mm total adult length. Secondary specialist sources report about 3-6 years captive lifespan and audible stridulation; those are not primary life-history measurements.
- The widely repeated 8 mg/kg/frequent-sting/no-toxin-death account was recovered only through a 2013 paper whose risk paragraph cites secondary sources. It is not presented as primary clinical surveillance.
- A 2026 oral LD50 greater than 2000 mg/kg is an oral animal result, not a sting-severity measure. No LD50 is used to predict a human outcome.