Care for tadpoles

I usually combine a breeding coupe of D. tinctorius with a smaller type of frog.  So I keep a couple D. tinctorius 'brasil' together with a group of  D. ventrimaculatus 'missing-black'.  After a few years, from that breeding group D. ventrimaculatus there was  only one male left. The 'brasils' however, are still breeding and apparently this was interesting for this single male.

He gladly wanted to show  for the camera  that he had not yet forgotten how to transport a tadpole . Apparently it does not matter him that the tadpole is from other frogs.  My first impression of  this happening was, that the tadpole at night crawled accidentally on the back of the frog, passing the night in the filmbox.
After a day with the larva on his back, he brougt it to the water in the front of the terrarium.