Aye <img src="/images/graemlins/smile.gif" alt="" /> Clawed frogs are 3-5" at maturity, depending on gender. Mine is a bit too small at present to determine sex--first I thought boy, but as it grows it might be a girl...I wish I knew! <img src="/images/graemlins/wink.gif" alt="" />
Sorry to hear your frog died <img src="/images/graemlins/frown.gif" alt="" /> I don't know anything about the hardiness of dwarf frogs, but I know that keeping frogs and fish is slightly tricky because a lot of medicines one would use for fish, like ich medications, contain substances toxic to frogs. I'm constantly reading labels on anything I put in that tank, and they don't warn you at the pet store that any metal ions, for example, are toxic to frogs. If you have a tank with lid with any exposed metal on it (like on the light fixture), the water could become poisonous for the frog just from evaporation & condensation picking up metal ions. Tough stuff, frog rearing!
They're also more susceptible to the pitfalls of water chemistry since they're thin-skinned, so to speak. I walk on eggshells making sure my ammonia & nitrite are kept in check! With a messy goldfish that's a tough job <img src="/images/graemlins/wink.gif" alt="" />