Yellow and Black Walking Toads (Melanophryniscus stelzneri)
By Seth Doty
Note: The author would be extremely interested in obtaining some of the other species of Melanophryniscus. If you have any information concerning how or where he might legally acquire breeding stock please contact him at firstname.lastname@example.org
General Information: These toads are an easy to care for species from Northern Argentina, Paraguay, Southern Brazil and Uruguay. Most, but all, males are aprox. 25mm and females average about 30-35mm; however large females can reach 40mm in some cases. To my knowledge there are two sub-species generally available in the hobby. The larger and more commonly available of the two, has large yellow bars and swirls on the black background, and the ventral side of its feet and thighs in addition its “armpits” are bright red with the remainder of the ventral surface being yellow and black with often a few flecks of red on the yellow section of the belly. I believe this sub-species to be M. stelzneri fulvoguttatus. I have seen a number of examples of Melanophryniscus come in; in which the spots and bars are very nearly white, but these are usually mixed in with M. stelzneri fulvoguttatus and as this is the only difference I have been able to discern; I “believe” them to be no more than a slightly different color variation of M. stelzneri fulvoguttatus. The other occasionally available sub-species I am aware of is smaller, and most specimens are 20-25mm. It has far less yellow and more black coloration than the previously mentioned sub-species. What yellow there is tends to be in small flecks or spots instead of large bars and swirls, and in most specimens the ventral is completely red and black with no yellow at all, or at most a few small flecks. I believe this sub-species to be M. stelzneri stelzneri.
Temperatures: These toads are quite tolerant of the temperature range. The ideal range seems to be between 70 and 80 degrees. Occasional temperatures in the low nineties or down into the mid-forties have not been harmful to my collection although the toads are not very active at these times. I maintain the humidity at 60-80% the majority of the time as they are less active and hide when it becomes much higher or lower.
Housing and setup: When housing them a good rule of thumb is to allow a minimum of 2.5 gal. of tank space for each toad with no tank smaller than a five gal. and no more than 10 toads per tank no matter the size. Some might say this amount of space is to small but it has worked fine for me. I have had absolutely no problems nor have I observed any signs of stress from maintaining them long term in, what is by some standards, “crowded” conditions.
I use both pea gravel and locally collected topsoil for substrate; but it can be leaves, ground coconut husk or anything that doesn’t make the humidity too high with the amount of ventilation you use. A shallow small to medium size water dish should be provided.(I use an overturned Frisbee) Live or artificial plants, particularly pothos, are recommended as they improve the terrariums looks, and the toads seem to enjoy climbing up the plants. The toads are not very skilled climbers and often fall, but no harm seems to result. Keep in mind when setting up the habitat that, although they are very adaptable, they are reported to be from a savanna-type area where they are said to have grasses and small shrubs rather than bromeliads and similar plants.
Feeding: These toads tend to be very enthusiastic eaters. Feeding adults is no problem as long as plenty of small food items are maintained. Keep in mind that they eat a lot of food for their size. Pinhead crickets, fruit flies, termites, small harmless ant species, small silkworms, waxworms, and almost any other harmless insects of similar size are all acceptable food items. They are such eager eaters that my adults will crawl into the water section of the tank, where they only occasionally go although they swim fairly well, to eat the fruit flies that have fallen in and are crawling on the surface of the water.
Breeding: The breeding info given here is the method I learned by trial and error. It has worked well for me but it is certainly not set in stone and you may achieve better results by varying in one or more ways from my methods. I often vary somewhat from these methods myself. This description is only intended to offer a good starting point for someone that has no idea where to begin. Don’t be afraid to experiment a little.
I begin the breeding process by placing the female toads in a refrigerator at approx. 40-50F for approximately 4-5 days. This simulates “winter” and I have not found any more time to be necessary to simulate the females to begin to develop eggs. It is not necessary to refrigerate the males as I have found them to be simulated to clasp primarily by the “rain” but refrigeration can be done if desired and no harm will result. After removing the females from the refrigerator, place them in a small container at room temperature and feed them very heavily for approximately a week and a half. It is especially important to make certain that the females have all the food that they can possibly eat at this time or they may not develop eggs. After around a week and a half, put all the toads you wish to breed in a rain chamber. I prefer an ordinary household shower, as the water comes out more forcefully than most rain chambers. I feel that this more closely simulates the heavy rainstorms that precede breeding in the wild. Just make certain that there is no soap or similar products on or in the shower that could harm them. And also see that the drain is covered with wire or plastic netting so the toads can’t go down the drain! After taking the necessary precautions leave them in the rain chamber for approx. half an hour, then raise the water level to an inch or two in depth. At this time, put in a few things for them to climb out on,( sticks, plants, rocks ect.) and let the water run for the next hour. After an hour and a half in the rain chamber, remove the toads to a well-planted (pothos, sphagnum moss, etc.) gravel-based aquarium one-fourth land and three-fourths water with water depth 1-3 in. deep. The males may already be in amplexus when removed from the rain chamber. If not, they should be within a few hours of being placed in the aquarium. The eggs are usually laid by the following afternoon. If no eggs are laid by then, it becomes increasingly improbable that any will be. In that case, it is best to return the toads to their normal setup. The males will shortly release the females.
If You're successful...
In spawning, the female stiffens all her limbs and her sides begin to move violently as the male rubs her vent with the dorsal side of both his feet approx. five times before the female expels a small clump of 7-12 eggs. The male usually rubs the eggs briefly between his feet (presumably to mix the sperm and eggs well) and then, still holding the eggs with his back feet, sways his body well clear of the female, rocking from side to side until his feet touch a submerged plant, twig, rock, or something of a similar nature. The clump of eggs adheres to it. In my experience about three-fourths of the eggs are laid on the surface and are attached approximately half an inch under the surface to submerged plant stems. In about one fourth of them, the female dives several inches down, deposits the eggs when submerged and the male attaches the eggs to the under side of the leaves of submerged vegetation. The pair can produce up to about 250 eggs in the case of large females. However around 200 eggs seems to be the norm for average size female M. stelzneri fulvoguttatus in my colony. Normally, they lay the eggs at the rate of about one clump per minute; however, this can be highly variable. The water temperature that seems to be preferred for eggs and tadpoles is 74F-78F. I have raised tadpoles successfully at water temperatures from 68F-82F but at both extremes I suffered somewhat higher mortality than the norm. At a water temperature of 78 degrees, the eggs will hatch in about 48 hrs. but this may vary up to 12 hrs. each way.
Of Tads and Froglets
The 4mm tadpoles appear embryonic upon hatching and cling to the plants, sides of the tank or sink to the bottom of the tank for two days. After two days, the tadpoles begin to swim around more and begin to feed on algae or algae based fish food. The tadpoles should be given at least two square inches of space each, or they may exhibit bradyauxesis. After 7-10 days the tadpoles back limbs should become visible, and they will reach their maximum length of 14-18mm. In the next 5-7 days the front limbs will also emerge. Much care should be taken at this time as the froglets are very prone to drown. Within 36 hours of the emergence of the front limbs the froglet will complete the metamorphosis. The froglets are black upon the completion of metamorphosis and are only 4-6mm long! Needless to say without special precautions they are quite difficult to feed. Feeding them at this size is easily the most difficult part of raising them. Offer springtails, aphids, very small termites, harmless ants, tiny pillbugs, or almost any tiny insects. One trick that I have found useful for feeding newly metamorphosed froglets is to “stunt” wingless D. melanogaster fruit flies. This is accomplished by using a reduced amount of medium, just enough to cover the bottom of the culture jar. This greatly reduces the amount of food available to the larva and often will cut their adult size by a significant degree; particularly if the medium is kept fairly dry. Often the stunting is great enough that the larger froglets can feed on them immediately or shortly after metamorphosis. This is a great blessing to me as I am one of those people that have considerable difficulty maintaining the positively huge numbers of springtails cultures that necessary for such a project to succeeded for an extended period of time. The method currently use I use in conjunction with stunted fruit flies and I call it the “compost heap method”. This entails setting up an enclosure (usually a ten gal. tank for up to 60 or so 6-14mm froglets) several months before you will need it. Use about two inches of earth in the bottom and plant a few small clumps of pothos in one end of the tank. Then collect a handful or two of leaf litter and put it in the other end of the enclosure. Put some seed or deer Corn on top of the leaf litter. Then collect earthworms and adult pillbugs and add them to the mix. Mist everything down and cover the tank so as to allow little ventilation. Don’t be afraid of mold if it grows, it doesn’t hurt a thing, before you know it you will have a thriving colony of pillbugs, springtails, mites and various other tiny insects. When it is time for you to add the froglets it is advisable to increase the ventilation but do not permit the soil to dry out. The froglets will grow quickly in such a setup and with the addition of stunted D. melanogaster as needed they easily double or even triple their size in the first month. By then they have developed some of their yellow and red coloration and although the amount will continue to increase in the coming months they already resemble miniature examples the adults. They will also become easier to feed as they are able to consume normal wingless D. melanogaster at this size.