Unfortunatly the issue with these two species is not size, but toxicity. So no matter how much space you have their is still a possibility of one species (or both) poisoning the other to death. Also, I keep both species, and fbt will try to eat smaller newts.
If you're curious about vivarium construction I would suggest
amphibiancare.com (devin edmonds). My site has a few articles as well (freewebs.com/kapoktree).
Feel free to contact me at otis07_@hotmail.com with any questions.
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A room of herps.
www.freewebs.com/kapoktree

