Can Mealworms cause impaction in Leopard Geckos? (Full Guide)

Mealworms are a common and popular food for Leopard Geckos, but the risk of potentially deadly impaction worries many owners. In short: Yes, Mealworms can cause impaction, but only if the Leopard Gecko isn’t healthy, or is fed incorrectly.

In this post, we’ll go over all the details of impaction, how Mealworms can cause it, and most importantly, how you can avoid it.

What is impaction in Leopard Geckos?

Impaction is a condition where the lizard’s intestines are blocked by something that they have eaten, usually something indigestible. If left untreated, impaction can be fatal.

While there are home treatments that can help, they tend to work only on light impaction, before it gets dangerous. If you notice it too late, only a vet will be able to help.

How dangerous is impaction in Leopard Geckos?

Impaction, if untreated, can be deadly to Leopard Geckos. If you pay attention to your gecko, it shouldn’t come to that, though. You should be able to spot unusual behavior in time to watch for symptoms and start home treatment long before the impaction becomes fatal. More on symptoms and treatment later in this post.

How can Mealworms cause impaction in Leopard Geckos?

Mealworms can cause impaction in Leopard Geckos, but only in certain cases. With proper care, mealworms are entirely safe to eat for your gecko.

More specifically: Impaction from mealworms is usually caused by their hard, indigestible shell, from overfeeding, or feeding mealworms that are too large. Simply put, impaction comes from overloading the digestive tract of your lizard, which doesn’t happen through moderate feeding of mealworms, but rather if your gecko eats very hard shells, too many hard shells, or too much in general.

Impaction from a Mealworm’s hard shell

Mealworms are the larval stage of the hard-shelled Darkling Beetle. Before turning into a pupa and eventually the fully-developed beetle, the mealworm grows in size. During that time, its hard shell needs to be shed and regrown frequently, usually around 10 to 15 times.

After the mealworm sheds its shell, it is at its softest. This is the ideal time to feed the mealworm to your gecko.

If you wait for too long, the shell hardens over the next few days, before shedding again after around 5-7 days. You can recognize these cycles by their changing color: Freshly shed mealworms are very light, a white to cream color, then darken to a tan or brown color when the shell hardens.

Do your best to pick the right mealworms to feed your gecko – the ones that have recently shed, featuring a white to cream color and a shell that’s soft to the touch. This will reduce the risk of impaction from the shell.

However, there are more reasons and risks to be aware of, so keep reading.

Impaction from overfeeding Mealworms

As mentioned before, impaction is an overloading of the digestive tract, like clogged pipes. But not only indigestible shells can clog those pipes: Overfeeding your gecko can cause impaction as well.

While overfeeding on mealworms once is not going to cause impaction, overeating can cause digestive issues and obesity long-term, which can eventually lead to impaction. This can happen because many Leopard Geckos love mealworms and happily eat them, sometimes more than necessary. Since mealworms are relatively high in fat, this can lead to obesity if you don’t manage their diet properly.

Impaction from oversized Mealworms

A more immediate cause can be feeding your Leopard Gecko oversized mealworms – these can clog their digestive system, leading to impaction.

A good rule of thumb is to pay attention to two things: The size of the worm, and the gecko’s efforts.

A Leopard Gecko’s throat is about as wide as the space between its eyes. You shouldn’t feed them anything wider than that – this shouldn’t be an issue with mealworms, but is a good reference for any other food, too.

Similarly, small geckos shouldn’t be fed big mealworms. As a baby or juvenile Leopard Gecko, only small mealworms are safe for feeding. These are around 0.25 to 0.5 inches (about 0,6 to 1.2cm) long. As the gecko grows bigger, it can handle fully grown mealworms of up to a full inch in size.

The downside of having a baby or juvenile Leopard Gecko is that you may be buying mealworms while they’re young and small, but then they quickly outgrow the size that is safe to eat for your gecko. That’s why it’s a good idea to buy mealworms in small quantities, to avoid having to throw away most of them when they grow too much.

Impaction from substrate ingestion

An entirely different reason can be not the mealworm itself, but a side effect: If you use a substrate like sand or similar fine material in your gecko’s tank, the worm will likely crawl through it or burrow if given the opportunity. This can lead to your gecko ingesting some substrate while feeding on the mealworm.

Sand, just like the mealworm’s chitin shells, is indigestible and can cause buildup and longer-term, impaction in your gecko. To avoid this, place your mealworms into a bow or onto a surface that is free of substrate (like on a tile or on paper towels). If you’re unsure about what substrates are safe and healthy, use this list of ideal gecko substrates for guidance.

Impaction from an overall struggling digestive system

Sometimes, it’s not the mealworms at all – impaction is still essentially an overload of the gecko’s digestive system, which can also happen if the digestive system itself is struggling, and thus overloaded even by regular amounts of food.

For well-functioning digestion, your Leopard Gecko needs a warm place in its habitat. Make sure you have a warm side in the tank, heated by a heat lamp or heat map, and at the right temperature for your little gecko. Overheating or cooling down can cause slow digestion, and that can lead to impaction.

Always provide adequate heat sources and install a thermometer to regularly check the temperature in the tank.

Similarly, a healthy, varied diet, supplemented with vitamins and calcium, is important for geckos to avoid malnourishment and mineral deficiencies. If you’re not intentionally supplementing, gut-loading, and/or dusting your Leopard Gecko’s food, it’s most likely not getting everything that it needs! Read more about supplementing your gecko’s diet here.

How to avoid impaction from feeding Mealworms to your Leopard Gecko

To sum it up, here’s what you should do to minimize the risk of mealworm-caused impaction in your Leopard Gecko:

  1. Feed your gecko mealworms that are white or cream-colored – that’s when their shell is the softest and hast the lowest chance of causing impaction
  2. Feed your gecko the right amount of mealworms to avoid overfeeding
  3. Feed your gecko mealworms that are small enough – don’t feed a young gecko large mealworms (larger than 0.5 inches / 1,2 cm)
  4. Place the mealworms on an area that is substrate-free – like a feeding bowl, a tile, or paper towels. This helps avoid accidental ingestion of indigestible substrate
  5. Never feed your gecko exclusively on mealworms – they need a varied diet with different types of feeder insects – like Dubia roaches and crickets – to meet their nutritional needs (don’t forget about gut-loading and dusting for supplementing!)

Signs of impaction in your Leopard Gecko – common symptoms

In order to keep your Leopard Gecko healthy, make sure to check in regularly. The first symptom is usually constipation – so if you notice your gecko is pooping much less than usual for a few days, they might have a digestion problem!

If they do, they will likely also lose appetite – which is the next sign to watch out for. However, this may be caused by a variety of reasons, so don’t jump to conclusions if this is the only symptom you notice. It is a strong hint in combination with constipation, though.

The next sign would be lethargy and weight loss – without functioning digestion and little to no food coming in, your gecko would be low-energy and will display signs of weight loss. At this point, a visit to the vet is recommended, especially if you’re not very experienced with gecko care.

The final, most important symptom is a dark spot on your gecko’s belly. This can also be caused by other problems, but is almost always a reason to worry. If you see this, unless you know what you’re doing, take your little reptile to a vet and get an expert opinion on causes and treatments.

How to treat impaction in your Leopard Gecko at home

When you see early symptoms of impaction, but your gecko still seems to be doing okay, you can try simple home treatments before visiting the vet. Keep in mind that waiting too long until the impaction becomes serious increases the risk for your gecko, so don’t wait around for too long!

A warm bath

Just like for humans, a warm bath can be a very relaxing experience for your Leopard Gecko as well as boost digestion and possibly solving digestive issues.

If your gecko seems constipated, try one or two baths a day for 2 to 4 days – each up to 30 minutes long. Make sure the water is about as warm as the warm side of its tank, or about 86-92° F / 30-33° C.

While bathing, make sure that the belly is covered by water, but not the back – after all, you don’t want to risk your gecko drowning!

You can also gently massage the belly area, moving your finger downwards to promote digestion, with the focus on being gentle. You might feel that your gecko’s belly is slightly swollen – this is another sign of constipation.

Olive Oil

A good addition to warm baths can be olive oil – feeding your gecko just a drop of it can help boost digestive function. Put a drop of quality olive oil on your finger and gently feed it to your gecko. Move the drop of oil towards its mouth until your gecko begins licking it – but watch out and make sure that none of it gets into your gecko’s nostrils.

The oil acts as a gentle laxative, but it does take up to three days until it works. That’s why you should start using this treatment at the same time as you begin baths – if you don’t see results after 3-4 days, go to the vet immediately, rather than try different methods, as the risk of a serious impaction goes up the longer you delay.

Common Questions

Are mealworms hard to digest for leopard geckos?

Leopard Geckos should have no troubles digesting mealworms, unless their shell is at its hardest, the mealworm is too large for the gecko, or if too many mealworms are fed at once. Overall health also plays a factor, but a healthy Leopard Gecko should have no problems with eating or digesting mealworms.

Can a leopard gecko survive impaction?

If impaction becomes serious, it can pose a significant health risk to your gecko and can be fatal, but if noticed early, impaction or constipation can be treated and fixed easily.

How do you fix an impaction on a gecko?

When you notice constipation, lack of appetite, or a swollen belly, warm baths and a drop of olive oil, fed orally, can help improve digestion and get things going again. If this doesn’t work within 3-4 days, you should immediately visit a veterinarian.

Can you feed mealworm beetles to your Leopard Gecko?

Grown/evolved mealworm beetles should never be fed to a Leopard Gecko. Their shell is significantly harder than a mealworm’s shell, and will certainly cause digestive problems for your gecko.

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