circumfic/confix

The main case where {{confix}} is used with no base, as far as I know, is for Latin and Greek-derived words like aquaphobia. However, I really doubt whether the two parts of that word can really be properly called affixes.

The noun aquaphobia is a fine example. It is in my opinion a compound noun consisting of a head and a modifier. Here, phobia is the head while aqua merely modifies the head.

The concept of decompounding a word into a prefix and a suffix doesn't make much sence to me, since you always have a starting point, a base. And the starting point (or head) in this case is phobia not aqua.

But for the German terms this concept doesn't apply anyway. "Wasserangst" is a compound and "Aquaphobie" is considered a borrowed word with Latin and Greek roots, so no need here to decompound into a prefix and a suffix.