Tarantula (Cobalt Blue) — Food & Nutrition Products

The Cobalt Blue Tarantula (Haplopelma lividum) is an obligate carnivore that derives all of its nutrition from live prey. Unlike mammals or reptiles, tarantulas do not require supplemental vitamins or minerals in most cases, because a well-fed, gut-loaded feeder insect delivers a complete nutritional profile. The key nutrients this species needs include protein for muscle and exoskeleton maintenance, fat for energy reserves between meals, and trace minerals like calcium that support healthy molting cycles.

Because the Cobalt Blue is a fossorial species that spends the majority of its time in a burrow, its metabolic rate is comparatively low. This means it requires less frequent feeding than arboreal or highly active tarantula species. Overfeeding can lead to an oversized abdomen that becomes vulnerable to rupture from falls, even short ones inside the enclosure. Striking the right balance between adequate nutrition and overfeeding is one of the most important aspects of Cobalt Blue husbandry.

It is also worth noting that nutritional needs shift across the tarantula's life stages. Spiderlings and juveniles are in active growth phases and benefit from more frequent meals to support successive molts. Adults, particularly mature females who may go months between meals in the wild, can be fed on a much more relaxed schedule. Understanding these shifting requirements helps keepers avoid both underfeeding during critical growth windows and overfeeding sedentary adults.

Hydration is an often-overlooked component of tarantula nutrition. While the Cobalt Blue absorbs moisture from its prey, a shallow water dish should always be available. This species originates from the humid forests of Myanmar and Thailand, so access to water supports both hydration and the ambient humidity levels the spider needs for healthy respiratory function and successful molts.

The backbone of a Cobalt Blue Tarantula's diet is live feeder insects. Crickets are the most widely available and commonly used prey item, offering a solid balance of protein and fat when properly gut-loaded. When selecting crickets, choose specimens that are no longer than the tarantula's body length to prevent prey from injuring or stressing the spider. Uneaten crickets should always be removed within 24 hours, as they can harass a resting or pre-molt tarantula.

Dubia roaches are an excellent alternative and are often preferred by experienced keepers. They are quieter than crickets, less likely to escape, and carry a favorable protein-to-fat ratio. Their soft bodies also make them easy for tarantulas of all sizes to consume. Dubia roaches are particularly well-suited for Cobalt Blues because they tend to stay on the substrate level rather than climbing enclosure walls, making them more accessible to this ground-dwelling species.

Mealworms and superworms can be offered as occasional variety but should not form the primary diet. Their chitinous exoskeletons are harder to digest, and superworms in particular can bite if left unattended in the enclosure. For spiderlings, flightless fruit flies and pinhead crickets are appropriately sized prey items that pose no risk of injury. As the tarantula grows, prey size should scale up gradually to match the spider's increasing body size.

Regardless of which feeder insect you choose, gut-loading is essential. Feeding your feeder insects a nutritious diet of fresh vegetables, grains, and commercial gut-load formulas for 24 to 48 hours before offering them to your tarantula ensures the prey delivers maximum nutritional value. Think of gut-loading as indirect nutrition — you are feeding the food that feeds your spider.

Gut-loading is the practice of feeding feeder insects a nutrient-dense diet before they are offered to your tarantula. This step is critical because the nutritional content of a feeder insect is only as good as what it has recently consumed. A cricket that has been sitting in a bare container with no food offers far less nutritional value than one that has been eating fresh greens, carrots, and high-quality dry food for a day or two.

Commercial gut-load products are available in both dry and gel formulations. Dry formulas are typically grain-based and fortified with vitamins and minerals, while gel products serve double duty by providing hydration and nutrition simultaneously. Many keepers combine both approaches, offering a dry gut-load alongside slices of carrot, sweet potato, or dark leafy greens. Avoid citrus fruits, onions, and any produce treated with pesticides, as these can be toxic to both the feeder insects and the tarantula.

For keepers who maintain their own feeder colonies, consistent gut-loading becomes part of the regular colony maintenance routine. Dubia roach colonies, for example, thrive on a steady diet of fresh produce scraps and dry chow, which keeps them in prime nutritional condition at all times. This approach eliminates the need for last-minute gut-loading sessions and ensures that every roach pulled from the colony is ready to serve as a high-quality meal.

Prey preparation also includes sizing. A good rule of thumb is to offer prey items that are roughly half to three-quarters the length of the tarantula's body. Prey that is too large can stress or even injure the spider, while prey that is too small may not be worth the energy expenditure for an adult Cobalt Blue to capture. Matching prey size to spider size is a simple but important step that many new keepers overlook.

Tarantulas generally do not require direct supplementation the way reptiles or amphibians do. There is no need to dust feeder insects with calcium or vitamin powders, as the gut-loading process should deliver all necessary micronutrients. In fact, dusting prey items can sometimes deter a tarantula from feeding, as the powder may alter the taste or texture of the insect in ways the spider finds unappealing.

The one area where supplementation plays an indirect role is through the feeder insect colony itself. By providing your feeder insects with a calcium-rich diet — including items like ground eggshells, calcium-fortified dry food, or dark leafy greens — you ensure that the prey items carry adequate calcium to support your tarantula's molting process. This is especially important for fast-growing juveniles that molt frequently and need strong exoskeleton development.

Hydration deserves special attention for the Cobalt Blue Tarantula. This species requires higher humidity levels than many popular pet tarantulas, and dehydration can lead to molting complications that may be fatal. A shallow water dish should be present in the enclosure at all times, even though you may rarely observe your spider drinking from it directly. Many tarantulas hydrate by pressing their mouthparts against moist substrate or water droplets, so maintaining appropriate substrate moisture is equally important.

The water dish should be shallow enough to prevent drowning — a bottle cap or small ceramic dish works well for juveniles, while adults can use a slightly larger dish. Clean and refill the dish regularly to prevent bacterial growth. Avoid sponges in the water dish, as they harbor bacteria and are unnecessary. Fresh, clean water and a properly moistened substrate are all this species needs to stay well-hydrated.

While the Cobalt Blue Tarantula is a capable predator, not all prey items are safe or appropriate. Wild-caught insects should be strictly avoided because they may carry pesticides, parasites, or other contaminants that can sicken or kill your spider. Even insects from a seemingly clean backyard garden may have been exposed to lawn treatments, herbicides, or other chemicals that are invisible but deadly to invertebrates.

Certain feeder insects pose physical risks. Superworms and mealworms that are too large can bite a tarantula, potentially injuring it during or after a feeding attempt. If offering these prey items, consider crushing the head of the worm immediately before placing it in the enclosure to eliminate the biting risk while the prey is still fresh enough to trigger a feeding response. This practice is especially important for smaller or younger tarantulas.

Vertebrate prey such as pinky mice should not be offered to the Cobalt Blue Tarantula. While some keepers of very large tarantula species occasionally offer vertebrate prey, the Cobalt Blue does not reach the size that would make this appropriate, and vertebrate prey carries a higher risk of bacterial contamination and incomplete digestion. Feeder insects provide everything this species needs nutritionally without the complications that come with vertebrate prey items.

Finally, never offer dead or pre-killed insects unless they were freshly killed moments before offering. Decaying insects can introduce harmful bacteria into the enclosure, and most tarantulas will ignore prey that is not moving. The Cobalt Blue in particular is a species that relies heavily on vibration to detect prey, so movement is a key feeding trigger. If your tarantula refuses food, it is far better to remove the prey and try again in a few days than to leave dead insects sitting in the enclosure.

Establishing a consistent feeding schedule for a Cobalt Blue Tarantula depends primarily on the spider's age and size. Spiderlings and small juveniles should be offered appropriately sized prey every four to five days to support their rapid growth and frequent molting cycles. At this stage, the tarantula's metabolism is at its highest, and regular feeding helps ensure strong exoskeleton development and healthy weight gain between molts.

Sub-adults and young adults can transition to a weekly feeding schedule. One or two appropriately sized prey items per week is typically sufficient to maintain healthy body condition without overfeeding. Pay attention to the size of the tarantula's abdomen relative to its cephalothorax — a healthy abdomen should be roughly the same size or slightly larger. An abdomen that appears disproportionately swollen may indicate overfeeding, while a shrunken abdomen could signal dehydration or the need for more frequent meals.

Mature adults, particularly females, can be fed every ten to fourteen days. Cobalt Blues are not highly active spiders, and their fossorial lifestyle means they expend relatively little energy on a daily basis. Many experienced keepers report that their adult Cobalt Blues voluntarily fast for weeks or even months at a time, particularly in the period leading up to a molt. This is completely normal behavior and should not cause alarm as long as the spider has access to fresh water and shows no signs of dehydration.

Always remove uneaten prey within 24 hours. A tarantula that refuses food is almost certainly in pre-molt, and feeder insects left in the enclosure during this vulnerable period can injure or kill a molting spider. If your Cobalt Blue refuses food two or three times in a row, stop offering and wait for signs that the molt has completed before resuming the feeding schedule. After a successful molt, wait at least a week before offering food to allow the new exoskeleton to harden fully.

Because the Cobalt Blue Tarantula spends most of its time hidden in a burrow, monitoring its body condition requires a more observational approach than with display species. The most reliable indicator of nutritional health is abdomen size. A well-fed tarantula will have a plump, rounded abdomen that is proportional to its cephalothorax. If the abdomen appears wrinkled, shrunken, or deflated, the spider may be dehydrated or underfed and should be offered water and food promptly.

Conversely, an abdomen that is stretched taut and disproportionately large compared to the rest of the body suggests overfeeding. While this is not immediately dangerous, it does increase the risk of injury from even minor falls within the enclosure. For a fossorial species like the Cobalt Blue, this risk is somewhat mitigated by the fact that it rarely climbs, but it remains a concern worth managing through appropriate feeding frequency.

Molting is the most nutritionally demanding event in a tarantula's life, and successful molts are the best evidence that your feeding regimen is working. A tarantula that molts cleanly, without retained exoskeleton or deformed limbs, is receiving adequate nutrition and hydration. Conversely, difficult molts — including stuck exuviae, curled legs, or prolonged molting times — can indicate nutritional deficiencies or, more commonly, inadequate humidity. Tracking the frequency and quality of your tarantula's molts over time gives you a long-term picture of its nutritional health.

Keep a simple log of feeding dates, prey items offered, whether the spider accepted or refused food, and molt dates. This record becomes invaluable for recognizing patterns in your individual spider's behavior, predicting upcoming molts based on feeding refusal patterns, and troubleshooting any health issues that may arise. Even a basic spreadsheet or notebook entry after each feeding session provides useful data over the life of your tarantula.