Solenopsis invicta
Buren, 1972
Red imported fire ant
Temperature
24–30 °C
Humidity
50–70%
Colony size
50,000–250,000
Queen size
7–9 mm
Worker size
3–6 mm
Diet
Care Guide
Solenopsis invicta, commonly known as the red imported fire ant, displays a modest degree of polymorphism within the colony. The queen is the largest individual, measuring 7–9 mm, and is the sole reproductive engine behind colonies that can swell to an impressive 250,000 workers. Workers range from 3–6 mm, with larger individuals often acting as powerful defenders and foragers. Despite their small size, these ants are famous for their tenacity and the potent, burning sting that gives them their common name — a feature keepers should respect but need not fear with proper handling.
One of the most captivating aspects of Solenopsis invicta is their voracious feeding behavior. These ants are enthusiastic hunters and scavengers, readily accepting a diet of insects such as crickets, mealworms, and roaches. They also require a steady supply of sugar water for energy, and a high-protein diet is essential for brood development. Unlike seed-harvesting species, fire ants do not store grains; instead, they rely on a constant flow of fresh protein. Their foraging is swift and organized, making feeding time a thrilling spectacle as hundreds of workers mob a single prey item.
Care difficulty
Keeping Solenopsis invicta is best suited for intermediate keepers. While their founding is claustral — meaning the queen seals herself in a chamber and raises the first workers without needing food — the colony’s rapid growth, high aggression, and escape-proof requirements demand attention. Beginners may find their defensive nature challenging, but for those prepared, the reward is a dynamic, fast-developing colony.
Housing
A secure formicarium is non-negotiable. Fire ants are exceptional escape artists and can squeeze through the smallest gaps. Use tight-fitting lids, apply fluon or mineral oil barriers, and check for any cracks regularly. The nest should be maintained at 24–30°C with 50–70% humidity. A heated section and a cooler area allow the colony to thermoregulate. They do not require hibernation, so year-round activity is possible — a boon for keepers in colder climates. Provide a clean outworld with a constant water source, and expect heavy traffic; the colony will quickly fill every available space.
First days after purchase
Upon receiving your Solenopsis invicta colony, transfer them into their new setup as quickly and gently as possible. Place the formicarium in a quiet, dark location and avoid disturbance for at least 48 hours. Offer a drop of sugar water and a small piece of insect protein, but do not overfeed — uneaten prey can rot. Observe from a distance; the workers may initially appear stressed or defensive. With time, they will settle, and their characteristic rapid, coordinated movements will signal a healthy, thriving colony.