Melopoeus lividus

Melopoeus lividus, also known as the Cobalt Blue tarantula, hails from the dense forests and scrublands of Southeast Asia, particularly Thailand, Myanmar and neighbouring regions. In the wild, they’re found tucked away in deep, silk-lined burrows beneath the forest floor where they can avoid predators, sweltering heat, and monsoons. The native climate is hot and humid for much of the year, with regular temperature fluctuations between balmy days and slightly cooler nights. During the rainy season, the humidity soars, lending itself perfectly to the Cobalt Blue’s need for a muggy environment. If you’re after an exotic showstopper straight from the jungles of Thailand, you’ve found it.

An adult Melopoeus lividus typically reaches a diagonal leg span of around 12–15 cm. Females outsize the males, not just in size but also bulk, and they far outlast their male counterparts. Males tend to be leggier and a tad less robust, especially after their final moult. Juveniles start off quite small, but their notorious attitude is evident from the get-go.

Firmly fossorial by nature, Melopoeus lividus will spend the vast majority of its time hidden in a burrow, only venturing out for food or if something has disturbed their webbed fortress. In captivity, they are expert tunnel-makers and will take any opportunity to dig deep into a suitably generous substrate, often vanishing for days (or weeks) at a time. Give them the substrate depth they crave and you’ll be rewarded with a complex maze of tunnels. If you’re lucky, they might just create an entrance where you can catch a glimpse of those trademark cobalt legs.

Females can live anything from 12 to 15 years with good care, making them a long-term commitment (and friend who can’t judge your décor). Males, as is the case with most tarantulas, have a far shorter life—typically 3 to 4 years, often expiring not long after their ultimate moult. Make sure you’re prepared for the difference in longevity if you’re lucky enough to have a lady cobalt in your collection.

The Cobalt Blue boasts a medium to fast growth rate compared to other Asian species. Juveniles can go from spidery slip of a thing to a sapphire show-off in just a few years when fed well and kept warm. Consistent feeding, warmth and proper humidity are key to accelerating growth without risking health or a grumpy tarantula.

Let’s not sugar-coat it: the Cobalt Blue is as legendary for its bad attitude as for its show-stopping looks. Nervy, lightning-fast, and prone to dramatic threat displays, this isn’t the spider for a hands-on cuddle session (not that you should, anyway!). They’ll stand their ground, slap those legs, and scuttle back into their burrow faster than you can blink if bothered. That said, left undisturbed, they’ll spend their days as reclusive homebodies, only emerging after dark. Treat them with respect and space, and you can enjoy their antics from a safe distance.

Melopoeus lividus enjoys a warm environment mimicking the sultry jungles of its homeland. Aim for a temperature range of 24–28°C during the day, with a slight dip at night—nothing below 20°C though, or your spider might stage a sit-in. Heating can be achieved through a heat mat attached to the side of the enclosure (never the bottom for fossorials!) or with a gentle heat source in the spider room. Always use a thermostat for safety, and steer clear of anything that could bake your blue beauty. Avoid extremes or sudden swings, and ensure any heat source can’t be dug into or flooded.

Humidity for Cobalt Blues should be kept around 70–80%, reminiscent of their tropical rainforest origins. This can be maintained with regular, light moistening of the lower substrate and ensuring good cross-ventilation to avoid stuffy, stagnant conditions (nobody likes mouldy corners, least of all your tarantula). Always provide a shallow water dish, even if you rarely spot them sippin’. Avoid going overboard—soaked substrate will only irritate the spider or lead to burrow collapse. Proper balance is everything: moist, not swampy, and always fresh air.

Notoriously shy, Melopoeus lividus spends much of its time out of sight, deep in its burrow. That being said, bold individuals or those in optimal setups may surprise you with a nocturnal wander or a dramatic meal-time appearance. Their entrance tunnels can provide fleeting glimpses of blue limbs if you’re patient or lucky—sort of like a rare Pokémon sighting, but with more legs. Build the enclosure with a side-viewing window or strategically placed décor to increase your chances of spotting your secretive pet.

Cobalt Blues are prolific webbers, especially around burrow entrances and within their tunnels. Expect silk-lined passageways, intricate trap doors, and the occasional impromptu hammock. Their burrows often resemble a silk fortress with multiple exits and layers, making for a surprisingly complex and ever-changing structure. Watching them rework their home can be almost as entertaining as seeing their electric-blue legs flashing in the torchlight. Webbing also helps support their delicate tunnel architecture—think of it as tarantula scaffolding.

Slings enjoy a steady diet of pre-killed pinhead crickets, baby roaches, and the odd mealworm chunk every 3–5 days. Juveniles can handle larger prey, such as small locusts, crickets, or roaches once or twice a week. Adults are best offered one or two suitably-sized insects weekly, and are famously ferocious feeders—feeding tongs advised! Don’t overfeed; these spiders easily pile on the pounds (for a spider, anyway), which can make moulting tricky. Remove uneaten prey within 24 hours to prevent stress or accidents. Bear in mind, like all tarantulas, Melopoeus lividus may go on fasting stints, especially before moulting. A sudden refusal to eat? Don’t panic—just check for an upcoming moult or environmental issue.

A secure, escape-proof enclosure is a must, given the Cobalt Blue’s speed and tendency to test boundaries. Use a deep, sturdy container (minimum 30 x 30 x 40 cm for adults), with at least 20 cm of firmly packed, slightly moist substrate such as coco fibre, topsoil, or a mix. This depth allows for proper burrow construction. Add a starter tunnel or hide (bark tube or cork half-log) and they’ll quickly take it from there. Ventilation should be excellent, but avoid strong drafts. A shallow water dish is essential, even if you rarely spot them using it. Avoid live plants—they’ll likely be uprooted in a home renovation frenzy. Make sure the lid is tightly secured, and never open the enclosure without planning, as escapees are Olympic-level sprinters.

Recommended for experienced hobbyists due to their speed, defensiveness, and specific housing requirements. They’re certainly not for newbies or the faint of heart, but they can be a rewarding challenge for those confident with Asian fossorials. If you’ve worked with Old World species before and fancy a bit of drama (and those jaw-dropping colours!), you’ll find them a fascinating addition.

Melopoeus lividus is the poster child for ‘look, don’t touch’ tarantulas. With their dazzling electric-blue legs, powerful burrowing instincts, and larger-than-life attitude, they’re as captivating as they are challenging. Few spiders command such respect—both for their fiery temperament and jaw-dropping appearance. They’re ideal for keepers who want a bit of drama and aren’t afraid of an elusive housemate. Their webbing, burrowing, and occasional outbursts make for endless fascination. However, be honest about your experience and nerves—this species rewards patience and good planning, but they’ve sent more than a few hearts racing. If you crave a challenge and love a bit of spider theatre, the Cobalt Blue won’t disappoint.