hi purple, im pretty new to frog keeping and dont know alot about toads but i feed my frogs every other day, im sure they need food more than once a week... i saw a care site on fire belly toads and it said feed 2-3 times per week, and i think that cleaning them out once a month is a no go.... they build up toxins in the tank and that can make them sick. And definatly dont house any other species with them cause of the different toxins each species have thats probally why your frog died....you need partial water changes frequently to keep the water clean.
I hope this helps for now but someone who knows alot more will probally answer your question with more accuracy soon..... good luck!