Awesome thanks for the help manI have a biocube 14 with corys and a beta and love it. An angel would be quite nice as a centerpiece in the 29.
Just keep in mind that as these tanks were originally designed as saltwater setups they are not ideally suited to freshwater applications out of the box. Some things to consider are:
The lighting it comes with will probably be 10k and actinic. Depending on the size of the bulbs in the 29 you may be able to find some more suitable to a planted tank/freshwater. In my case the only options I had are those intended for saltwater so I went with 1 10k bulb, and 1 half 10k half actinic because I like the way the blue light helps to offset the yellowness of the 10k visually. Actinic bulbs do nothing for freshwater. I have decent growth of mosses and easy plants with this setup. Depending on if you want a planted tank I would suggest researching your options first.
Another thing to note is that the pump is quite strong and may create too much current in a freshwater setup. To regulate flow I installed a cheap ball valve which I highly recommend if you're having problems with your fish being blown around.
I have over the last few years had a couple of casualties due to fish jumping into the back chamber and getting blended in the pump input... I never did anything to block the chambers but it might be something to consider as it is a risk.
One other thing to think about is how much water volume and swimming space is actually available in a biocube. For example my "14" is really closer to 10 gallons in water volume. I have no idea how much water volume you would have in the 29. The back chambers tuake up space and will only be about half full with water
I know this goes way beyond your stocking question. Just thought I would give you some food for thought as I learned these things the hard way after switching from saltwater.