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How Many Black Soldier Fly Larvae Should I Feed My Pet?

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Table of Contents

How Many Black Soldier Fly Larvae should I feed my Pet?

Table of Contents

Black Soldier Fly Larvae (BSFL) can be an extremely nutritious food source for many insectivorous and omnivorous reptiles and invertebrate pets. But, there is a lot of confusing information on the internet about how many black soldier fly larvae you need to feed your pet. In this article, we have compiled all the information for each species of pet at each age. This information is based on legitimate science and veterinary publications. Plus, you can learn how to tell if your pet is becoming malnourished or overweight! Let’s dive right in…

Bearded Dragons

blsf for bearded dragons

How Many BSFL for Bearded Dragons?

  • Young Bearded Dragons (1-3 months old) = ~20 ¼” BSFL 2-3 times per day (about 400 small BSFL per week)
  • Juvenile Bearded Dragons (3-9 months old) = 20-40 ½” BSFL 2 times per day
  • Maturing Bearded Dragons (9+ months old) = 10-15 ¾” BSFL every other day 

Bearded Dragon Dietary Needs

It’s important to note that Bearded Dragons are omnivorous as adults. Young dragons and juveniles will eat mostly insects, though adult dragons need fruits, vegetables, and greens to make up more than 50% of their diet.

Since Bearded Dragons are omnivorous, their dietary requirements are a bit more complicated than obligate insectivore diets. As juveniles, dragons will eat almost exclusively insects and should be offered as many insects per feeding as they will consume. Each dragon will have a slightly different appetite, so the above numbers of insects are simply a starting point. If your dragon is not eating all of the BSFL, you can reduce the number you offer each meal. But, if they are eating all of the insects and continue looking for more, you may need to increase these numbers slightly.

Young dragons usually have a voracious appetite and will eat massive amounts of insects if they are offered. If your BSFL were raised on a healthy and varied plant-based diet, they will be gut-loaded with the appropriate nutrients your growing dragon needs. Since BSFL are much higher in fat than crickets, you should monitor your juveniles for signs of obesity. However, most juveniles will simply grow faster and not become obese until they reach maturity.

At about 4 months of age, most Bearded Dragons will begin eating plant material. Their consumption of plant material will slowly increase as they age, and many older adults may stop eating insects altogether. 

Checking for Obesity or Malnourishment

It is easy to avoid metabolic bone disease and other conditions in dragons if a large variety of plants and insects are offered at different times. You can read our list of Bearded-Dragon-Approved vegetables, and should generally offer a variety of insects to give your dragon a diverse nutrient source.

Obese bearded dragons are typically getting too much fat in their diet. This is certainly a possibility when feeding BSFL, as these insects are relatively high in fat content. Juveniles will typically metabolize this energy and convert it into growth, but older individuals may start to develop large fat stores. There are two basic methods of monitoring your dragon’s weight:

  • Weigh your dragon regularly. Once they are about a year old, this weight should plateau and remain steady. If your dragon keeps gaining weight after this time, it may start becoming obese.
  • Visually inspect your dragon. Signs of obesity include a large, bloated gut and general lethargy. Cut back the amount of fat in your dragon’s diet, and offer more plant materials.

On the other hand, underfeeding your dragon can lead to a malnourished condition. Losing weight as an adult is a sign of malnutrition. You may also see that your dragon is losing muscle mass, has excess folds of skin, and is generally lacking energy. Other signs of malnutrition include an inability to shed properly, especially around the eyes and face. Some dragons can become duller in color and look pale if they are suffering from nutrient deficiencies. In this case, you may need to increase the diversity and amount of food you are offering in order to balance their diet.

Veiled Chameleons

blsf for veiled chameleons

How many BSFL for Veiled Chameleons?

  • Young Veiled Chameleons (1-3 months old) = ~6 ¼” BSFL 2 times per day
  • Young Veiled Chameleons (3-6 months old) = 10-15 ½” BSFL per day
  • Juvenile Veiled Chameleons (6-10 months old) = 15-25 ½” BSFL every other day
  • Maturing Veiled Chameleons (10+ months old) = 5-10 ¾” BSFL every other day

It should be noted that some Chameleons will not take BSFL, as they may prefer crawling and flying insects that do not stay on the ground. However, they may enjoy adult black soldier flies as a treat.

Veiled Chameleon Dietary Needs

Veiled chameleons (and all chameleon species) are obligate insectivores. With their long, sticky tongue, chameleons are adapted to catch crawling and flying insects from quite a distance. Many chameleon owners prefer crickets to BSFL because crickets will readily explore the terrarium, giving their chameleon a chance to use its tongue at a distance. Some chameleons may eat BSFL, though you should put them in a clean bowl so your chameleon does not ingest any substrate that their sticky tongue may pick up. Chameleons can suffer from calcium deficiencies. BSFL have high levels of calcium balanced with phosphorous, so they can make great supplements to help balance your pet’s diet.

Checking for Obesity or Malnourishment

Obesity is a problem for many chameleons, especially females. Female chameleons have a large food drive to consume as many insects as they can catch. In the wild, this helps them build up crucial fat stores. They need these fat stores to produce eggs on time. You should be aware that BSFL have a very high fat content. Feeding too many BSFL to a mature female chameleon can lead to obesity, which you will be able to measure through your pet’s weight as well as physiological changes such as a rotund body and areas around the spine that bulge out.

On the other hand, a malnourished chameleon will look very skinny. Near the spine, a malnourished chameleon will have slight depressions and the spine will form a sharp crest down the back. Chameleons also have very telling color changes when they are not feeling well. They may become a dull, pale color or they may get very dark in coloration. Both can be signs that something is off. Healthy and happy chameleons should be a bright, vibrant color (usually green in veiled chameleons). BSFL are great for malnourished chameleons, if they will take them. If not, you can try dubia roaches or other larger insects with a higher fat content than crickets. 

Leopard Geckos

bsfl for leopard geckos

How many BSFL for Leopard Geckos?

  • Young Leopard Geckos (0-4 months old) = 4-10 ¼” BSFL per day
  • Juvenile Leopard Geckos (4-10 months old) = 5-10 ½” BSFL 5-6 days a week
  • Maturing Leopard Geckos (10+ months old) = 5-15 ¾” BSFL 2-3 times a week

Leopard Gecko Dietary Needs

Leopard Geckos are obligate insectivores that have a voracious appetite for almost all types of feeder insects. A common rule for leopard geckos is to feed 2 appropriately sized bugs per 1 inch of your leopard gecko’s length. Keep in mind that leopard geckos (like most obligate insectivores) have very specific calcium and phosphorus requirements. The ratio of calcium to phosphorus in the diet should be about 2:1. Anything too far outside of this ratio can lead to calcium deficiencies that can manifest as poor bone health, issues shedding, and digestive problems.

In the wild, leopard geckos are nocturnal hunters that eat a wide variety of prey items. So, it is best to rotate your feeder from time to time to keep your gecko engaged as well as expose them to a variety of tastes and nutrients. As leopard geckos age, their appetite decreases. You can gradually reduce the amount and times you feed your gecko as they age.

Checking for Obesity and Malnourishment

Most veterinarians use two different signs to measure for malnourishment or obesity within leopard geckos. First, watch their tail as they grow. Leopard gecko tails should be plump, but not quite round. If the tail starts to shrivel at all, your gecko is likely not receiving enough of the proper nutrients. If their tail starts to bulge out or if their sides start becoming overly plump, this may be a sign of obesity (though it can also mean a female is gravid with eggs). You can also measure your animal’s weight regularly to ensure that they grow at a steady rate to adulthood, when their weight should plateau and remain steady.

Tokay Gecko

bsfl for tokay gecko

How many BSFL for Tokay Geckos?

  • Young Tokay Geckos (0-4 months old) = 4-10 ¼” BSFL per day
  • Juvenile Tokay Geckos (4-12 months old) = 5-10 ½” BSFL 5-6 days a week
  • Maturing Tokay Geckos (12+ months old) = 5-15 ¾” BSFL 2-3 times a week

Tokay Gecko Dietary Needs

Tokay geckos have very similar dietary needs to leopard geckos, though they are slightly smaller. However, tokay geckos will not start eating until after their first shed - which can be a few days to weeks after hatching. While tokay geckos are thought to be some to be obligate carnivores, some owners state that their pets will take soft fruit as a treat. 

Like leopard geckos, tokay geckos will feed on a wide variety of insect prey. BSFL can make a great starter insect for juvenile geckos because they have a balanced calcium and phosphorus profile and have a high fat content for quick growth. However, adult tokay geckos may get obese if fed a diet of only BSFL. Mixing up the feeder insects you offer is always recommended. 

Checking for Obesity or Malnutrition

Like leopard geckos, tokay geckos can be monitored visually and by regularly checking their weight. Juveniles should steadily gain weight, while adults should level off and maintain weight. The tail can be a great indicator of obesity or malnutrition. If the tail becomes plump or misshapen, this is a clear sign of obesity. 

On the other hand, a dwindling tail with loose skin can indicate that your gecko is losing weight or not getting enough nutrition. These lizards often become lethargic when they are too fat, and likewise lethargic when they are malnourished. A healthy lizard will regularly be active and enjoy hunting feeders. Color changes are also easy to spot in tokay geckos due to their normally vibrant colors. A pale or dull-colored gecko is often a clear sign that your pet is not healthy.

Crested Geckos

crested geckos and bsfl

How many BSFL for Crested Geckos?

  • Young Crested Geckos (0-4 months old) = 2-5 ¼” BSFL per day
  • Juvenile Crested Geckos (4-12 months old) = 5-10 ½” BSFL 4 days a week
  • Maturing Crested Geckos (12+ months old) = 5-10 ¾” BSFL 2-3 times a week

Crested Gecko Dietary Needs

Crested geckos are slightly smaller than both leopard and tokay geckos. As such, they should receive a slightly smaller amount of feeders, fed slightly less often. Like the other types of gecko, they prefer to hunt at night and should be offered fresh insects right before dusk. Like tokay geckos, crested geckos will also accept soft fruit treats at irregular intervals. 

Black soldier fly larvae are slightly more balanced in calcium to phosphorus ratios compared to crickets, meaning you may need less supplementation on these insects. However, they are much higher in fat. So, you need to carefully monitor your pet’s weight and mix up feeder insects if your crested gecko starts gaining weight too fast. 

Checking for Obesity or Malnutrition

Crested geckos have a much thinner tail than tokay and leopard geckos. However, since they are skinnier in general, any slight changes to their physical form can be indications of weight gain or loss. Tight skin is a sign of obesity, whereas very loose skin is a sign of malnutrition. Monitoring your crested gecko’s behavior can be one of the best ways to determine dietary problems, as crested geckos will quickly lose energy if they are overweight or malnourished. Like other geckos, the best way to ensure your gecko is getting a balanced diet is to offer a wide variety of insects that are gut-loaded with calcium-rich nutrients.

Crested geckos will also show the common signs of calcium deficiency and metabolic bone disease including swollen limbs, disfigured bones in the spine, hips, and tail, as well as general weakness. Though crested geckos are usually a solid brown color, an unhealthy gecko may become dull in color. These issues can be avoided by feeding gut-loaded insects or regularly dusting your feeder insects with mineral and calcium supplements. If your gecko is too weak to eat, one trick is to crush up some BSFL and wipe a little on your lizard’s nose. The lizard will like the paste off, getting important nutrients in the process. Repeat this process until the lizard has enough energy to hunt on their own. 

Emperor Scorpion

blsf for emperor scorpions

How many BSFL for Emperor Scorpions?

  • Young Emperor Scorpions (1-2 weeks) = 0 BSFL (Simply feed the Mother Scorpion*)
  • Juvenile Emperor Scorpions (First molt - 5+ Inches) = 1-2 ¼” BSFL per week (outside of molting**)
  • Maturing Emperor Scorpions (7-8 Inches) = 3-5 ¾” BSFL every other day
    * Mother scorpions will tear up food to feed their young. Simply feed the mother a little extra and she will take care of her scorplings.
    ** When you notice the start of molting (a dull exoskeleton color), withhold all food. Wait until the new exoskeleton has hardened before feeding again.

Emperor Scorpion Dietary Needs

In general, people tend to overestimate how much food scorpions require. Many scorpion species can fast for a week or more between feedings, though they will take food more often. Scorpions are obligate carnivores and will eat a wide variety of insects and even small pinky mice (once in a while). Just be sure not to offer your pet too many prey items at once, or your scorpion could become stressed out or even get chewed on by excess insects. 

Checking for Obesity or Malnourishment

Though obesity and malnourishment are hard to see in a scorpion, paying attention to their behavior can help you gauge whether their diet is sufficient. An obese scorpion may become extremely lazy and lethargic, whereas a hungry or malnourished scorpion may be ravenous when you offer food. If you notice either of these behaviors, adjust your food offerings accordingly. Though supplementation is not as necessary for scorpions, you can ensure your scorpion is getting the nutrients and minerals they need with minor supplementation every few weeks or by using gut-loaded insects. 

One way to predict obesity in a scorpion is to observe how fast they are molting. Most scorpion species go through approximately 6 molts before they become adults, which can happen in as few as 6 months. Before reaching adulthood, nearly all the energy they consume is converted into growth, which speeds up molting. So, if your scorpion is molting every 1-2 months, there is a good chance you are overfeeding it. When it reaches adulthood, there is a chance it will become obese. 


bsfl for tarantulas

How many BSFL for Tarantulas?

  • Young Tarantulas (<½”) = 1-2 ⅛” BSFL 1-2 times per week
  • Juvenile Tarantulas (First molt - 5+ Inches) = 1-2 ¼” BSFL per week (outside of molting**)
  • Maturing Tarantulas (7-8 Inches) = 3-5 ¾” BSFL every other day
    ** Molting tarantulas should not be fed. But, directly after the exoskeleton hardens your tarantula will be very hungry. It can be offered slightly more food at this time to help it gain weight and rehydrate.

Tarantula Dietary Needs

Though tarantulas do not need vitamin supplements, they should be fed gut-loaded insects that have a good balance of nutrients. BSFL are great for this task, as they are typically fed a wide variety of food scraps that make them very nutritious. That being said, spiders typically thrive when fed a high diversity of insect species - similar to the diet they would eat in the wild.

Juvenile tarantulas may need to be fed more than twice a week since they get all of their water through the food they eat. Larger tarantulas can drink out of water dishes, but young tarantulas can easily drown in even shallow bowls. Therefore, you should offer a few small prey items multiple times a week to ensure that young spiderlings stay hydrated. Like other invertebrate pets, the molting cycle of a tarantula can be lengthened or shortened depending on how much food they receive. If your tarantula seems to be molting too often, simply cut back the amount of food you are giving it. Most spiders and scorpions can go a week or more without food (as long as water is available). 

Checking for Obesity or Malnutrition

Tarantulas can easily be monitored for signs of obesity or malnutrition based on the condition of their abdomen. Generally speaking, the abdomen should be approximately the same size as the thorax. Since the abdomen is much more flexible than the abdomen, it will quickly change with your spider’s overall condition.

An obese spider will have a greatly expanded abdomen that is much larger than the width of the thorax. At the extreme size, the abdomen may even drag on the ground. Food should be greatly reduced for an overweight tarantula. On the other hand, a malnourished tarantula will have a shriveled or slowly shrinking abdomen. This can also indicate dehydration since spiders store water and fat in their abdomen. BSFL can be a great feeder to regain the health of a malnourished tarantula because they are high in fat and water content, allowing your spider to quickly replenish their abdomen. 


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