I just recently joined and I have been reading some of the vivarium posts and have come across many that ask about mixing various frogs, toads, newts ect. and fish together. It is good that you are asking questions before going through with anything, because many people don't and their animals pay. Mixed species tanks are not a good idea, especially for anyone who is not experienced with all the species going into the tank. Here are some things to consider
1) many frogs (i.e. treefrogs and bombia frogs) will eat anything that comes their way, if it can fit in their mouth they will try to eat it. i have fire bellied toads and i have seen them try to eat eachother everytime i feed them, of course they can't because their mouth isn't that big, but if there was an animal such as a newt that was longer and skinnier, it could get eaten.
2) toxicity, most caudates (newts and salamanders) are toxic, most are mildly toxic, where if exposed for a short period of time might not appear, but if kept together for more than a day or two, can have devastating effects on other species in the tank. fire bellied newts, oregon or rough skinned newts, all cycops species are toxic so should not be kept with anything but their own species.
3) habitat requirements, unless the animal lives in the same area, chances are they don't have the same requirements, newts need more water than frogs. newts usually need a minimum of half water, half land, and frogs usually need a water dish. toads need a water dish, but a dryer habitat, that if was wet/moist constantly would give it skin rotting/lesions. As far as african dwarf frogs with fish, i personally have never done it, but have heard it can often be sucessful with PEACEFUL fish such as mollies and platies.
So think about it before you put two different species in the same tank, because chances are it wouln't end up the way you had hoped. I have around 30 reptiles and amphibians as well as fish, so if you need help with vivariums or herp care I would be glad to help. Reply to this or PM me if you have any more questions, and good luck! I would also be glad to help with vivarium construction. Edited by fish_4_all