In this frog species, listed as “least concern” (LC) on the Red List, two forms are distinguished on the basis of their more or less constant color patterns and different distribution ranges, whereas a third, intermediate, form is highly variable.
The highland form inhabits moist premontane forests, not only primary, but also secondary forests, the margins of plantations and even parts along roads. These areas are usually at 550 m a.s.l., where average temperatures vary between 22 and 26˚C and sometimes decrease to as low as 17˚C. A tree-dwelling highland form is known, usually perched at 0.5-1.5 m above the ground on vegetation, which can be found on the ground only occasionally but can live on trees up to heights of 8 m.
The highland R. imitator lives in Cordillera Oriental in the east of the Departamento San Martín, Peru, at 250-1,000 m a.s.l..
The lowland form of this species can be found in primary forests and forest remnants of a more secondary character, where it inhabits lower vegetation up to heights of 1.5 m above the ground, but is also commonly living on the ground. In such places the temperatures rage from 26 to 30˚C during the day, and around 22˚C at night.
This form lives in lowlands to either side of the Río Huallaga, at least from Shucushyacu to the Río Paranapura in Departamento Loreto, Peru, at 160-300 m a.s.l., then further north to Jeberos.
Another form, the so-called fantastica form, is known to inhabit areas similar to the natural habitat of the lowland form, with slightly lower temperatures. These areas include the passage of the Río Huallaga in the Departamento San Martín in Peru, at around 200 m a.s.l..
The highland form of R. imitator resembles in its exterior R. variabilis. The ground color of the upper side is light yellowish, yellowish orange, greenish or bluish, with large black spots that may be fused to form an almost stripped pattern. The resulting light interspaces are already an intermediate character, linking it to other forms. A typical specimen also has two black dots that the nostrils on the snout, which is a known distinctive feature that also led to the name “two dots” for respective frogs and permits (in most cases) to differentiate them from the very similar “one dot” (R. variabilis). The frog’s ventral side can be light gray to bluish, usually yellowish at the throat and the black spots are somewhat smaller than those on the back. Some irregular black dots can also be seen on the gray, bluish or greenish limbs.
The lowland R. imitator has black sides and back with five, usually regular longitudinal median lines in yellow or orange extending from the tip of the snout, dorsolaterally from the anterior margins of the eyes, and ventolaterally as a continuation of a supralabial stripe that extends to the armpit and on from there. These five lines are commonly linked on the snout right before the eyes by a crossbar. Both limbs and the ventral side of the body are light blue with some irregular, small, black dots. The throat can be either yellow or orange with black dots.
The fantastica form of R. imitator is very similar to R. fantastica, with the upper and lower sides black and an orange to light copper-colored pattern, often light gray on the limbs. More or less regularly shaped bands and stripes mark the dorsal side, whereas the stripes are often wide and so reduce the black background to mere spots. Lines on the limbs usually twist or form a reticulated configuration. The ventral side is very coarsely marbled with black and orange and there are five, usually not quite regularly shaped longitudinal lines ventrolaterally, dorsolaterally and medially. The limbs can be bluish with some irregular black spots.
Because the males are often aggressive towards each other, it is highly advisable that this species should only be kept in pairs in a spacious rainforest terrarium of the Types I or IV, or also Type V. Its bromeliad vegetation should divide the tank into numerous stories, while the always slightly moist black film containers, mounted at various levels in a horizontal or slightly oblique position pointing to the rear, are accepted as spawning sites. The maximum day temperatures should take into account the origin of the frogs, frequent misting and a high level of relative humidity are preconditions for successful breeding. This species feeds on aphids, springtails, fruit flies, firebrats, white woodlice and the smallest of crickets.
Mainly because of its uncomplicated propagation and its interesting behavior, R. imitator ranks among the most recommendable poison frogs for the terrarium.