My Favorite Thumbnail: Ranitomeya variabilis ‘Southern’
I’ve kept and bred several species and locales of Ranitomeya over the years, and I have to say that I really enjoy woking with Ranitomeya variabilis ‘Southern’ more than any of the others. They are beautiful, fecund, hardy, and they can be kept in groups. Ideally, they should be kept in pairs, but they usually don’t show aggression when kept in groups. I keep mine in groups of 5-7, without any problems.
Ranitomeya variabilis ‘Southern’ is a thumbnail poison dart frog native to the eastern Andean foothills (300-1200 m) of Peru, particularly within the Huallaga drainage and nearby rainforest habitats. They are associated with bromeliads, leaf axils, and other water-holding plants where reproduction occurs. Adults spend much of their time in low vegetation and understory foliage rather than exclusively on the ground. They are slightly larger than the ‘Highland’ morph, with more green and blue coloration, often with lime-green dorsums transitioning to blue hindquarters. This locale is marked with large black blotches and spots. Like other poison frogs, they are diurnal, excellent climbers, and males establish small territories and advertise with a soft buzzing call.
Their reproductive strategy is one of the most fascinating among dart frogs. Eggs are laid in small water-filled sites such as bromeliads, leaf axils, etc. The males guard the clutch, and after hatching, the male transports tadpoles individually on his back to separate bodies of water. Tadpoles are predatory and can be cannibalistic, so natural separation is important.
In the wild, they feed on ants, mites, small flies, and tiny arthropods from leaf litter and vegetation.
They are extremely hardy in captivity, and their care is similar to other thumbnails. I keep all of my adults in 18x18x24” enclosures in groups of 5-7. Sure, you can keep them in smaller enclosures, but I feel strongly about giving them more room to establish territories within the enclosures. I know plenty of hobbyists who keep their breeders in 12x12x12” and 12x12x18” enclosures, without issues.
I’m not going to go into detail about the enclosure in this tutorial. There are several other tutorials where I go into great detail about enclosure construction. Provide your thumbnails with plenty of plants, including bromeliads, Philodendrons, and other suitable tropical vivarium plants. Driftwood, cork pieces, and branches can be used as hardscape. There is no need to provide any standing water. Light the enclsoure with an adequate LED made for freshwater aquaria or terraria/vivaria.
For breeding purposes, I put Tad-Pools and large film canisters in the enclosures as egg deposition sites. I also keep the bromeliad axils watered as additional laying sites. The females will lay 4-8 eggs on vegetation or in or near water. I let the eggs hatch in the enclosures, then I pull the tadpoles and raise them primarily separately. I’ve keep tadpoles in small groups with pretty good success, but I do not recommend it due to cannibalism.
The tadpoles take anywhere from 2-4+ months to morph into froglets. Once they have morphed, you can transfer them to a froglet growout enclosure. Please refer to tutorials about froglet growouts. They will initially feed on springtails and step up to fruit flies.
Ranitomeya variabilis ‘Southern’ is one of my absolute favorite thumbnail poison dart frogs because they are beautiful, bolder than many other thumbnails, and they are easy to breed. Give ‘em a shot!