Ephebopus cyanognathus

🔤 Taxonomy

Ephebopus cyanognathus West & Marshall, 2000 is the accepted name. It was described from French Guiana and has not undergone the repeated genus changes seen in many older hobby species. The trade name “blue fang” refers to the metallic blue chelicerae, but labels should always retain the scientific name because several Ephebopus species look similar when young.

English common names used in the hobby:

• Blue fang tarantula
• French Guiana blue fang

📌 Description

This is a medium-sized, powerfully built, obligate burrower from humid tropical forest. Adults usually reach about 10-14 cm diagonal legspan. Females may live roughly 10-15 years under steady care; mature males are slimmer and usually survive only a few years in total.

The blue chelicerae are striking, but most of the spider will often be hidden below ground. E. cyanognathus is quick, defensive when its retreat is opened, and capable of throwing unusual urticating hairs from the pedipalps. It suits an experienced keeper who values burrow architecture and feeding behaviour more than constant visibility.

☠️ Venom

All tarantulas possess venom, but no controlled clinical evidence supports calling the bite of E. cyanognathus medically significant. That does not make a bite harmless: the venom is poorly characterized, individual reactions differ, and the large fangs can produce deep punctures and secondary infection.

The more likely routine exposures are urticating hairs and a fast defensive bolt. Ephebopus carries type V urticating hairs on the pedipalps rather than only on the abdomen. Avoid handling, keep the enclosure below face level, wear eye protection when dismantling an old retreat, and never blow on the spider. After a bite, wash the wound, seek urgent medical advice for severe pain, spreading swelling, breathing difficulty, faintness, or eye exposure, and do not apply a tourniquet or cut the wound.

🌍 Distribution

The species is documented from French Guiana. Field observations place all life stages in shaded primary lowland and montane wet forest, where they construct a flared silk entrance leading into a simple tubular soil burrow. This evidence is more useful than a generic “rainforest humidity” number: the retreat stays buffered and moist while its entrance remains aerated.

The captive enclosure should therefore provide deep shape-holding earth, leaf litter around a starter burrow, a shaded position, and cross-ventilation. It should not reproduce outdoor rainfall by keeping every surface saturated.

🌡 Climate across the native range

Monthly climate normals from reviewed GBIF occurrence locations:

Weather data by WorldClim v2.1 · Monthly normals queried by Herpeton Academy from raster values; relative humidity is derived from vapor pressure and mean temperature.

Location references use GBIF.org occurrence data where available; original occurrence records retain their source dataset licenses.

⚖️ Legal status

The official CITES Appendices and the current EU wildlife-trade annexes were checked on 2026-08-05; Ephebopus cyanognathus was not found in them. The Bern Convention is not relevant because the species is not native to Europe. Non-listing does not prove that a specimen was collected or exported legally.

French Guiana is an overseas department of France, and wildlife collection, possession, export, import, sale, and transport can be controlled separately from CITES. Buy only a captive-produced animal with a dated invoice, breeder identity, scientific name, and any required transfer or import records. Check local dangerous-animal and landlord rules before purchase.

🤌 Husbandry

Keep one spider per enclosure. Provide the finished burrowing setup before introducing it; repeatedly digging out a hidden tarantula creates stress and an avoidable bite or escape opportunity. An adult enclosure around 30 x 25 x 30 cm is adequate if at least half its height is filled with substrate and the lid locks securely. Do not leave a long empty drop above the surface.

Pack a 15-20 cm layer of unfertilized topsoil mixed with coco fibre and a little clay or excavator soil so that tunnels hold. Angle cork bark into the substrate and press a starter hole beneath it. The spider can then extend a tubular burrow without the keeper excavating it. Tiny spiderlings may use raised web retreats at first, so include a small slanted cork strip as well as diggable substrate.

Quarantine a new arrival for at least 6-8 weeks away from other arachnids. Use separate tongs and water equipment, record feeding, posture, molts, and any mites or phorid flies, and retain the original label. Do not force a newly shipped spider to eat; offer water, darkness, and an intact retreat first.

Plan every maintenance task before opening the lid. Work inside a larger empty tub, have a catch cup and stiff card ready, and use long tools. If the burrow entrance is sealed, assume premolt or rest and leave it closed. Routine records of acquisition, source, molt dates, meals, and refusals are especially useful for a species that may remain hidden for weeks.

💡 Lighting

No UVB or basking lamp is required. Give 10-12 hours of indirect room light and an undisturbed dark period. Bright lamps above a deep enclosure can heat and dry the upper layers while the keeper assumes the burrow is still safe.

If plants are used, place a low-output LED outside the enclosure and verify temperature at the substrate surface and near the retreat. Never use coloured night lamps or direct sun through glass.

🌡 Heating and temperature

Maintain about 22-26°C by day with a cooler 20-22°C option and a modest night drop. These are captive working ranges, not a claim that the spider experiences constant air temperature in nature; a deep burrow buffers daily heat.

Warm the room first. If supplementary heat is unavoidable, put a thermostatically controlled low-power source on one side, never beneath the substrate. Measure with a digital probe. Persistent temperatures near or above 28°C, especially with saturated air, increase dehydration and oxygen stress.

💧 Humidity and water

Keep the lower substrate consistently damp enough to hold a tunnel, while allowing the top centimetre and the burrow mouth to approach dry between waterings. A practical instrument reading is often 70-85%, but substrate condition, ventilation, and the spider’s access to water matter more than chasing a display number.

Provide a shallow, stable water dish once the spider is large enough to use one safely. Pour water slowly down one enclosure corner or overflow the dish slightly so moisture reaches lower layers. Do not spray the animal, flood the burrow, or accept persistent condensation. Sour odour, fungus, mites, and a wet sheen across the whole surface mean the enclosure needs more airflow and less water.

🌿 Enclosure and decoration

Use cork, leaf litter, and a few light artificial or live plants as cover around the entrance. Heavy stones and hard ornaments can collapse into excavations or injure the abdomen and should be excluded. Vent holes must be smaller than the carapace of the smallest occupant and arranged for cross-flow, not only in the lid.

The enclosure need not be bioactive. Springtails can help process mold, but they do not replace removal of prey remains or correct excessive moisture. When rehousing is necessary, transfer the whole cork retreat if possible rather than exposing the spider with tongs.

🪳 Feeding

Offer captive-reared crickets, roaches, or locusts no longer than the spider’s abdomen. Spiderlings can take pinhead prey or freshly killed pieces twice weekly; juveniles usually feed every 5-7 days; well-conditioned adults commonly need one or two appropriate insects every 7-14 days. Adjust by abdomen condition, not a rigid calendar.

Drop prey near the burrow mouth and remove it within 24 hours if it is not taken. Never probe the tunnel to confirm a feeding response. Stop feeding when the spider refuses repeatedly or seals the retreat, and remove all live prey during premolt. Wait until the fangs are fully dark after a molt—several days for juveniles and often 7-10 days for adults—before feeding again. Calcium and vitamin powders are unnecessary.

🩺 Common problems

• A wrinkled abdomen or tucked posture can indicate dehydration; provide clean water and review the lower substrate without flooding the retreat.
• Continuous wall climbing often means the surface is too wet, compacted incorrectly, or lacks a usable starter burrow.
• Mold, mites, or phorid flies point to wet leftovers, stale air, or excessive watering; remove the source and correct ventilation.
• A sealed entrance and long fast are usually normal premolt behaviour. Digging the spider out can cause a fatal molt injury.
• A fall, ruptured abdomen, leaking hemolymph, uncoordinated movement, or a genuinely stuck molt requires urgent advice from an exotics veterinarian familiar with arachnids.

Never use household pesticides, essential oils, mite treatments, or disinfectant fumes around the enclosure.

📌 Conclusion

Ephebopus cyanognathus rewards a keeper who can maintain a deep, humid but breathing burrow and perform maintenance without exposing the animal. Its speed, defensive response, hidden lifestyle, and unusual urticating hairs make it a poor first tarantula, even though its temperature needs are uncomplicated.

📚 Sources and further reading

• World Spider Catalog entry for Ephebopus cyanognathus — accepted taxonomy and distribution, accessed 2026-08-05
• GBIF species entry for Ephebopus cyanognathus
• West, Marshall, Fukushima & Bertani: retreat architecture and habitat use in Ephebopus
• Tom’s Big Spiders: keeping moisture-dependent tarantulas — comparative husbandry, not species-specific limits
• CITES Appendices and EU wildlife-trade regulation — checked 2026-08-05