Quote Originally Posted by Glenn View Post
I have a similar setup; the sub is about 7" deep.

My frog is an adult though.
There shouldn't be a problem as long as you replace the substrate regularly and mix up the soil every so often.
You should also avoid making the substrate overly wet, which along with sub replacement and mixing, will help alleviate problems with pooling and stagnant water.

That all said, you should probably keep it in something smaller until it grows into the tank. As it stands now, it looks like he can't even get into or out of the water without jumping high (if he can manage it at all).
What filter are you using and how often you change the water? I wanna do something similar

mmahek - there is no such a thing as a substrate too deep but you need to change it every month and stir it once in a while. Stagnant water, bacteria is a case when substrate is mud like, and/or not deep enough.
The only drawback of deep substrate is that a frog might burry itself very deep and you wont see him, but that is not a frog problem but yours