Desk/Stand Strong Enough for Tank?

[pandaparties]

So i built a desk/organizer for my son a while back and recently replaced his 30g fish tank that was on it with a 55g. The 55g is rimless 1/2 inch glass and a lot heavier, not to mention the extra volume. I have yet to fill it. When I built the desk I wasn't exactly thinking strength, just utility. I have pictures of it below, as well as some crude drawings i made of the structure which is all 2x4s. All the connections were made with coated decking screws (3 inches typically), the paneling is just 1/2 ply and the top is maple butcher block. Anyone with experience on this know if its strong enough to hold a tank this size? I could probably sister the 2x4s on the end where the tank will sit but it might be a pain and not sure if its overkill. Also not sure if the way i built it is prone to any shearing forces etc (though it feels really sturdy). Any help would be very very appreciated! It's in my kids room so i want to be extra sure there's no risk of collapse.

Front View - Total length is 8ft long, 24inch deep

Back View

Top view - The bottom is the same but the the 2x4s running from front to back are positioned on one side of each vertical post.

Actual pictures (it's since been painted/finished, but his room is dirty and i'm too lazy to clean it up and take new pictures)

 

[KrisReef]

If you are worried about shear can you add a sheet of plywood onto the backside? Even some diagonal 2x4 on the back would handle that issue. The desk looks very solid with the frame and top that you have.
Field test would require you and him to stand up on top of the desk and do the “twist” or hat dance and evaluate the motion in the system.

Make a video in case my evaluation is flawed

 

[pandaparties]

If you are worried about shear can you add a sheet of plywood onto the backside? Even some diagonal 2x4 on the back would handle that issue. The desk looks very solid with the frame and top that you have.
Field test would require you and him to stand up on top of the desk and do the “twist” or hat dance and evaluate the motion in the system.

Make a video in case my evaluation is flawed

Ha! We'll definitely give that a shot! And the plywood backing might be a good call, I'll have to see if I can do that or at least the diagonals. Thanks for the input