That doesn't sound like a good idea to me. I'll try not to be too preachy here, but even if he's kept those together for years that still seems like a bad combination. I'm surprised that the other newts can withstand the toxins of the tylotriton, not to mention the potential for disease, or the fact that P watl grows to a much larger size than the other species, up to a length three to four times as long as the orientalis - I've fed longer worms to P watl.