Sized for far larger geckos. Even the smallest dubia nymphs and mealworms are typically too wide and too tough-bodied for an animal that weighs a few grams, creating a real choking and impaction risk. Skip these entirely for this species regardless of age — they belong on a crested or leopard gecko's menu, not a mourning gecko's.

Far too large-bodied and far too fatty for a 2–4g gecko — 22% fat content in an insect that's also oversized for the mouth. No good reason to offer these to a mourning gecko.

High acidity can irritate the digestive tract and isn't part of this species' natural diet. Skip oranges, lemons, limes, and grapefruit entirely.

Contains persin, a fungicidal toxin considered dangerous to many animals. Every part of the plant — fruit, skin, pit, and leaves — should be kept well away from the enclosure.

Lethal to reptiles generally — fireflies produce lucibufagins, defensive steroid toxins that cause rapid death if ingested. There is no safe amount. Never feed any wild-caught bioluminescent insect.

Any insect from your garden or an outdoor space carries pesticide residue, herbicide contamination, and parasite risk with no reliable way to test or clean it, and most are the wrong size regardless. Only feed captive-bred insects from a reputable supplier.

Widely marketed as "reptile safe" because it was assessed for dogs and cats, not reptiles — it appears on the Reptiles Magazine toxic plant list. Despite being an extremely common, hardy, humidity-loving vine that would otherwise suit a tropical enclosure well, it should be avoided given how much time a mourning gecko spends investigating and resting on foliage.

Also contains calcium oxalate crystals and appears on multiple reptile toxic-plant lists despite superficial resemblance to safer climbing vines. Avoid, especially given how much foliage-time this species spends.

Contains calcium oxalate crystals and is toxic if grazed on. Its humidity preference would otherwise suit this enclosure, but toxicity rules it out entirely.

On the Reptiles Magazine toxic plant list. Contains triterpenoid saponins and falcarinol, both toxic on ingestion, despite being a common, hardy climbing vine that would otherwise suit an arboreal setup.

Extremely toxic to virtually all animals — contains cardiac glycosides that cause heart failure even in small doses. Keep entirely away from any reptile enclosure.

One of the most toxic plants to animals generally. Every part contains cycasin, causing severe liver failure. Never place near a reptile enclosure.

The entire genus produces a milky latex sap causing severe burns and irritation on contact, and is toxic if grazed. Also poorly suited to humid conditions regardless of toxicity. No Euphorbia species should be used.