Building a FishTower in the Pond

Why would an Aquarium only be for inside use? I made one in my Pond, sort of Watch Tower, or Panorama Suite for my Pond Fish. Easy to make and.. They love it. Watch yourself.
Edit: Material used:
alfer®combitech® system connect 23.5 mm
and Dennerle Nano Cube 60L
Edit: To improve stability it is recommended to make the legs connected below the same way as on Top. Only 4 legs was shown not stable enough, Placement in the pond then requires an even ground to avoid tilting.
B.T.W. Music is Long Stroll by KevinMacleod, (Free youtube music)
Copyright, Camera and Mastering by Luxusburger