Illness/Sickness: Do Newt Skin Poisons Diffuse into Water? (Frog died mysteriously)

I know that it is generally considered not a good idea, but I did some species mixing. I have had two CFB newts for about 9 months, an apple snails and an infestation of tiny pond snails that came from a plant in my 10 gallon tank. Anyway, I thought it would be cool to add an african dwarf frog, despite the recommendations against mixing species. For 3 weeks everything seemed fine, the frog and the newts generally got along, I never saw them fighting, the newts would eat first, then the frog would go in when they were done, the frog seemed fine, the newts have been fine, everything seemed to be going well.

However, suddenly, the other day I was going to feed them, and I found the frog was dead. Now I'm not sure what killed him. He wasn't showing any signs of illness at all, no bloating, no discoloration or anything. Even after he died, the only thing abnormal was that he was lying upside down, not moving and his eyes had clouded over. Now my only theories are that despite looking fine he was sick; that maybe he ate a pond snail and choked; or that over time the newts emitted enough toxins from there skin that it built up to high enough level to suddenly kill my frog. Is that what might have happened, does the water build up poison levels? Or do newts only release their toxin when something is touching them or bothering them?

What do you guys think was the most probable cause of death for my deceased Kermit?

Have a read of this:

Newt Toxins

And this:

The Toxicity of Newts

And this:

Mixing Disasters

Another possibility is that the frog died of chytrid...which is supposedly quite common in petstore bought ADF's.

Chytrid is a very possible reason. It would also mean that now your newts are infected...(provided they weren´t already).
That mix was a very bad idea for several reasons...i hope you learn from it though.

By the way i don´t think it was a toxin issue...very unlikely.

You'll never know what killed Kermit unless you had it's body sent off for examination.

As for chytrid, I bet every one of us has it in our collections.

In addition to the other things mentioned, pet shop ADFs are mass produced, and have a reputation for being weak and inbred. So there are many possible reasons that the frog didn't make it.

Aren't African frogs warm tropical species, living in water above 20ish degrees c. Most newts I thought could live happily at 16 degrees.
Just my thoughts, this also happened with my common frog I found in a pond.