Raising Thumbnail Dartfrog Tadpoles (Ranitomeya)
Raising Thumbnail Dartfrog Tadpoles (Ranitomeya species)
by John P. Clare
This information refers specifically to Ranitomeya imitator (formerly Dendrobates imitator) but it applies well to all species of the "Thumbnail" genus, Ranitomeya.
Ranitomeya imitator "Tarapoto" tadpole. Photo ©2010 John P. Clare / FrogForum.net
There are 2 general approaches to raising thumbnail dart frog tadpoles. The first is to let the parents care for the tadpoles and feed them with unfertilized eggs. The other approach is to remove the eggs or tadpoles from the terrarium. Here I will talk about how I care for tadpoles outside the terrarium.
I like to leave the eggs in the terrarium until 1-2 days before they are due to hatch. Waiting longer risks letting the male start transporting and interfering with his efforts may result in the loss of a tadpole mid-transport. The photo below shows 4 Ranitomeya imitator "Varadero" tadpoles at about this stage:
Ranitomeya imitator "Varadero" tadpoles, a few days prior to hatching. Photo ©2010 John P. Clare / FrogForum.net
You can just make out the external gill filaments (thin pink threads). The tadpoles resorb these gill filaments about 24 hours before they are due to hatch. In the case of the 4 in the photo, they were laid on a bromeliad leaf. I used a sharp knife to cut the base of the leaf from the plant and then removed the entire leaf. The leaf was then placed in a film canister with some water in the bottom, and then placed in a small uninhabited terrarium to complete their development. The film canister is placed upright, with the leaf sticking straight up out of it. I check daily on the tadpoles. Once the external gills are gone, the tadpoles become more active and the jelly around them begins to soften. Once the jelly loses its shape, the tadpoles often break through the inner membrane so they no longer are curled inside a sphere, but more elongated. It is at this point that I gently remove each tadpole from its jelly and place it in a small deli cup like those in the photo below, one tadpole per cup. I use a couple of pins to pierce the jelly carefully and free each tadpole. Some people use a plastic spoon or the butt of a metal spoon to scoop eggs directly off the leaves without having to damage the plant, and this is an option too.
Each cup contains a piece of java moss. This breaks up the monotony of the circular cup and allows the tadpole to browse at its leisure. Each cup contains distilled water. I find their water requirements to be quite different to species like Dendrobates tinctorius. Large dendrobatids seem to require "tadpole tea" (water with lots of tannins from decaying leaves). Distilled water will often be harmful to such tadpoles that are kept in it for more than a day or so. Thumbnails, being off the ground in small bodies of water, don't have these tannins to any great extent in the wild, and due to regular rainfall, the water in their pools is refreshed constantly, with water that contains little or no dissolved nutrients, very much like distilled water. So, I don't use tadpole tea at all for thumbnails. They also seem unaffected by distilled water for water changes. Here's how I raise my Ranitomeya imitator (these are all the "Varadero" race):
Imitating Dart Frog tadpoles, Ranitomeya imitator "Varadero", at various stages of development. Photo ©2010 John P. Clare / FrogForum.net
I cover the cups with sheets of glass - in the above photo, you can see a single sheet covers 12 cups. The glass minimizes evaporation and allows me to see into the cups. There is no seal around the edge of the cups so air can still get in and out. Temperatures are 72-76 °F (21-25 °C). I feed mostly with the small size New Life Spectrum "Thera" pellets, 1-4 pellets every 3 days or so, the number of pellets depending on the size of the tadpole. I occasionally feed with an algae based pellet (perhaps 1 every 14 days), and I will also drop a few live fruit flies into each cup every now and then. The glass sheets prevent the fruit flies escaping, and the tadpoles go to the surface and prey upon the writhing flies. I carry out near complete water changes when things start to look a bit discolored and debris accumulates. I use pure distilled water.
When the tadpoles get both front legs, I pour off most of the water, then I take the deli cup and put a lid on it, and then put it partially on another lid so that it has a water part and a dry part. The froglet crawls out over the next few days and as soon as the tail is nearly gone I put the deli cup (kept at an angle) in a planted grow-out terrarium, with the deli cup's lid off so the froglet can crawl out when it is ready.
Imitating Dart Frog, Ranitomeya imitator "Varadero", in the process of resorbing its tail. Photo ©2010 John P. Clare / FrogForum.net
I generally add a few springtails to such a container to provide food, as well as feeding stunted Drosophila melanogaster from old fruit fly cultures. I once added far too many springtails to a grow-out container and the stress of springtails every where all the time led to the frogs dying, one by one, so ensure you don't go overboard on the springtails.
First published on Sunday September 19th 2010. Last updated Sunday September 19th 2010 - First published version.
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