They are basically the same, one (Aquatic) has all the pieces you need to connect it, you just have to figure out mounting and such. The other (Aquatic Life) has the same part all wrapped up in one complete unit, total plug and play...
For those of you who got a green toadstool from me, I glued a toothpick to the frag plug in order to keep it in position to attach itself. If it is protruding, feel free to cut off the exposed portion and the base of the toadstool will grow over it.