What size should live feed insects be?

What size should the live feed insect be to fit the hobby animal? 

In this article, we take a closer look at the problem and come up with some rules of thumb in relation to various hobby animals.

When feeding your hobby animal/pet with live insects, always make sure that the insects are a suitable size.

If the insects are too small, the hobby animal will usually not be particularly interested, either because it does not notice the insect at all, or perhaps rather because the hobby animal instinctively understands that it does not pay to sacrifice energy to hunt and devour their prey, there is not enough meat on.

On the other hand, the insect must not be too large either.

Some hobby animals instinctively abstain from animals they literally cannot yawn over, but some animals seem to be just legally optimistic.

There are many examples of hobby animals in the worst case being suffocated in too large prey, or in more fortunate cases have been able to make do with constipation and digestive problems.

In theory, one can imagine that the hobby animal in the wild has easier access to a wide range of prey in different sizes, and thus can select appropriate sizes.

In captivity, they have to make do with the prey they are presented with to a greater extent, so here the responsibility lies with the animal keeper.

There are no clear guidelines, but there are a few rules of thumb that are good to know.


Most lizards often swallow the insect in more or less whole condition, and as a rule of thumb, the insect should therefore not be wider than the distance between the lizard’s eyes.

Most often, it will be the case that adult lizards can easily take most adult insects, while lizard cubs can more suitably settle for insect nymphs in different stages.

Very long worms such as earthworms can be problematic for some lizard species.


The common rule of thumb is that the animal should not be larger than the spider’s body.

In other words, adult Tarantulas will be able to immediately take all types of adult insects, whereas there may be insect nymphs that must be used for smaller spiders and “slings”.

Praying mantis

The mantis is even an insect, but it does not go the way of prey larger than itself.

So with an average size of 5-8 cm, an adult kneeling can take all the usual adult-sized feed insects.

The very small kneeling nymphs can advantageously be fed with slightly smaller prey, but after a few ham changes, they are ready for adult sheep chickens, cockroaches, etc.


A general rule of thumb for scorpions is to use feed insects the size of the scorpion’s claw.


Many fish appreciate live feed, but as a general rule, the feed must be very small.

Depending on the species and size of the fish, excellent feed animals can be small mealworms, smaller larvae, banana flies and possibly larger flies as well as nymphs of e.g. chickens and locusts.

Rodents and birds

Several species of rodents and birds like to eat insects in addition to the diet.

The animals usually find out for themselves and there are no special requirements for the insect size.