Truth is, in the past, I have built custom multiple species vivaria. I have in fact even built a few for myself. Three separate times, the "customers" wanted either a specific newt or salamander included on the species list. I did not know any better at the time, I was a fish person, so I built some beautiful units that could theoretically hose the multiple species comfortably.
All three times resulted in disaster.
What customers reported back to me:(Note, I did not choose or stock the animals, I merely set up/constructed the custom vivaria)
First case scenario: Ambystoma tigrinum, Hyla cinerea, various invertebrates. Result:With in three months A. tigrinum ate everything. No joke. These guys are predatory eating machines. 350 dollar 100 gallon viv with one tiger in it that stayed buried most of the time.
Second case scenario: Mail order leopard frog tadpoles, Eastern Spotted Newts, Bull frog. Result: well fed bullfrog followed shortly by bullfrog death after newts went "missing"...950 dollar, 6'x6'x6' paulaudium (finest one I have ever built so far) currently still being used to grow houseplants.
Third case scenario: "Pac Man" frogs, Firebelly newts, fire belly toads, and multiple anolis Result: one (the largest) well fed pac man frog, three fatally injured FBN. Customer ended up with a 175 gallon 700 dollar terrarium with the biggest PacMan frog you have ever seen living in it.
My own mistake mad early on in my aquaria hobby: Ambystoma mexicanum, Cordoras, Neon Tetras, Betta Splendens, Cherry barbs, and a small Necturus. (very large schools of fish) Result: A well fed, badly injured axolotl, and a Necturus with a cory cat lodged in his gullet. Necturus died a few days later. Axolotl recovered, but was very raggedy looking for the next few years. Oh, and I was out about three months of work setting up a 200 gallon tank and about 75 bucks worth of fish.
Now, since this topic has come up recently and resulted in much argument, flamespraying and rude posts, I will add in here that these are my personal experiences.
Others have had different experiences. I myself had had great success with various interspecies reptile set ups, fish set ups, and even a few multiple species scorpion set ups.
I do not condone "species mixing" when amphibians, especially when caudates are involved. I have seen nothing but heartbreak, unecessary animal death and suffering, and lots of wasted money. All caudates are carnivores, quite a few are active hunting predators, others are sit and wait types. Ambystomids in particular follow the "Laws of Axolotl" (in my signature).
Please do not think that I am attempting to insult you or your idea. Personally, I would love to do huge vivaria based on multiple species from various environments around the United States, however, it is the animals themselves that prevent me from doing this.
Your set up may in fact work if you do it. You may never have an issue, or you could discover the hard way wht so many of us learned the hard way. "Toxins" will be the least likely issue. Predation will most certainly be an issue.
However, this is just my experience with the subject. I have been unable to ever find hard data with valid, verifiable sources to back up what myself and others experienced, either for or against this subject.
Because my posts in this thread are opinion based on actual observed situations, please use this information as you see fit.
