Introduction

These relatively small (20 – 50mm), very colourful and active frogs are currently split up into four genera - Dendrobates, Phyllobates, Epipedobates and Minyobates. There are currently sixty-five recognised species, but new species and sub-species are still being classified. They are often referred to as poison arrow or poison dart frogs but this is misleading due to the fact that only three species (Phyllobates terribilis, P. bicolour and P. aurotaenia) are known to be used by American Indians to tip the darts for their blowguns. Poison frogs make fascinating terrarium inhabitants, being fairly easy to keep and active during daylight hours (diurnal). Nowadays many species are captive-bred. Such specimens can be a better choice, especially for beginners, than imported animals which can be difficult to acclimatise.

Distribution

Poison frogs inhabit mostly humid rainforests of South and Central America, ranging from Nicaragua in the Northernmost range, down to Peru through to Bolivia / Paraguay borders in their southern-most range. Most species live in warm valleys, but some have been found in cooler mountain forests at altitudes of up to 2000m.

Description

These extremely colourful, and highly variable, frogs come in virtually all the colours of the spectrum, from bright reds (Dendrobates pumilio), to bright green and black (D. auratus) to bright blue (D. azureus). Not all are as brightly coloured but all are very beautiful in their own ways. There are also many colour variations within a single species. This is clearly illustrated by Dendrobates tinctorius and D. auratus, which have numerous forms ranging from very dark with flashes of yellow and green to vibrant yellow frogs with blue legs (D. tinctorius citronella). Other species, such as Dendrobates. pumilio, are also highly variable.

Sexing can be difficult in younger frogs but, as a general rule, males are often smaller than females, have thicker toes and their vocal sacs can often be seen as a small greyish area on the throat.

Captive care

Selecting your frog

Always select frogs which are in good condition. Do not be tempted to purchase sick or skinny frogs as these will inevitably die. Many people make the mistake of taking such specimens home, hoping to pull them around. Unfortunately this rarely happens, so be sure to pick animals which look healthy and which appear to be feeding. Imported animals are available on occasion but these can often be difficult to acclimatise, so it is probably best to select captive-bred frogs.

The larger species such as Dendrobates auratus, D. tinctorius and D. leucomelas feed on a much larger variety of foods than the smaller species and will take small crickets as well as fruit flies, so these are probably better for beginners.

Terrarium equipment

As a general rule, most poison dart frogs inhabit lowland areas and live amongst leaf litter and in small burrows, although some species are more arboreal and will inhabit Bromeliads growing higher up on tree stumps. This habitat is relatively easy to recreate in the terrarium. Temperatures in the rainforests do not often vary that much and in captivity a maximum day time high of 25 degrees C and night time low of 20 degrees C should be a guide. As with most amphibians, a slightly lower temperature will do far less harm than excessively high temperatures.

All-glass terrariums with mesh ventilation at both top and bottom generally work well as they provide adequate air circulation and prevent air from stagnating but also allow the necessary humidity. Many substrates can be used (bark chips, sphagnum moss are two commonly used examples) but I find tree fern slabs (Xaxim) covered with leaf litter works well. I provide pieces of cork bark for my animals to use as hides.

Daily misting provides the necessary humidity to prevent the skin of the frogs from drying out and can also aid in plant growth, especially Bromeliads. Bromeliads can make an attractive decorative feature and can serve well as retreats and breeding areas for many species. Planting your terrarium with real plants makes it into a real focal point and provides an excellent and naturalistic habitat for the inhabitants. If you do not want the extra work of maintaining real plants an excellent range of artificial alternatives are now available from most good reptile shops. It is a good idea to provide a shallow water bowl, but make sure that the frogs can climb out easily and that the depth does not exceed ½ inch. These measures should prevent accidental drowning.

Poison frogs should be exposed to a 12 hour day / night light cycle, a fluorescent light connected to a timer will produce a natural lighting source and will aid plant growth.

Feeding

Poison frogs eat large quantities of very small prey, so ensure that you have access to sufficient foodstuff. Ants are the preferred food source in the wild, but captive animals will feed readily on fruit flies and micro crickets. Smaller species and young froglets will accept springtails and other small aphids. Most foods are readily available at local pet or reptile specialists, but fruit flies and springtails are easy to cultivate yourself if supply is difficult. A good vitamin and mineral supplement should be used on a weekly basis.

Breeding

Poison frogs are readily available as captive bred animals, reflecting the fact that captive breeding is not overly difficult. Adults are often very territorial so it is best not to overcrowd the animals. Two to five animals will make a suitable size breeding colony. Most frogs will be sexually mature at around fifteen months of age and many species will to some extent be sexually dimorphic at this age. Males tend to be somewhat more slender and have pads on the front toes.

Make sure your frogs are in optimum condition before attempting to breed from them. Increasing humidity, such as regular misting with luke-warm water can trigger many species to breed. Make sure the terrarium requirements match the needs of your frogs for breeding. Some species lay their eggs in bromeliad funnels, whereas others will lay eggs in streams or pools of water.

I find covering a petri-dish filled with water with a coconut husks works well with some species. A small hole cut in the top of the husk will provide access and should be just large enough to allow the frogs to pass through. A leaf should be placed in the dish and will be used for depositation of the eggs. A cheap and easy alternative to a coconut husk is to cut the bottom off a soft drink bottle and cut a small access hole, but do ensure that there are no sharp edges.

Once the adults have become used to the nesting site the male will lead the female inside where mating will take place. Disturb the frogs as little as possible during the mating period. Up to fifteen eggs will be laid, hopefully on the leaf provided.

If the eggs are left in situ the parents will tend them but most keepers remove the eggs for incubation. The incubation temperature is actually the same as the adult frogs are maintained at so leaving them in situ is not necessarily a problem. The main problem associated with eggs is fungus. This can largely be avoided by regular checking and removal of infertile eggs as the "go off". All things being well, the tadpoles should hatch in about fifteen days.

Most Phyllobates and Dendrobates species can be raised on fish flakes and defrosted gnat and mosquito larvae. Tadpoles can be reared in shallow aquaria with adequate filtration and suitable plants, but be aware of cannibalism.

After about twenty-five days, the hind-legs should start to develop and at around forty days the colour and pattern will begin to show. At around fifty days, the front legs will appear and the tail will start to be absorbed. Once metamorphosis starts to take place the froglets should be segregated from the tadpoles. A tank, or plastic container, with a gentle slope, facilitating a wet and dry area makes the most suitable habitat for the juvenile frogs. At this stage cannibalism is no longer a problem and the young can be raised together. Froglets can be reared on springtails, fruit-flies and micro-crickets.

Conclusion

Poison frogs are extremely attractive, relatively easy to cater for and make fascinating captives. The sheer variation in the different species will ensure that every frog lover will have their own personal favourites. The fact that they are diurnal makes them ideal for densely planted terrariums and their willingness to breed in captivity will ensure that their popularity will increase for years to come.

In my opinion they are without doubt the most attractive and interesting amphibians you could wish to keep.

References and bibliography

Heselhaus, R. (1988) Poison arrow frogs Their Natural History and Care In Captivity. Stuttgart. Eugen Ulmer GmbH& Co

Walls, Jerry G. (1994) Jewels of the Rainforest – Poison Frogs of the family Dendrobatidae. Neptune City. T.F.H. Publications, Inc.