You basically want to build a rough opening around 7', with a ton of weight on top. A pair of LVL's that rest on notched 4x4's should work fine.
There is well over 2,000 lbs in that setup, but it's evenly distributed around all the sides. In your case the front weight will be distributed to the sides of your reptile opening.
I'd build it like typical house framing. Stud walls, plywood sheathing thats glued and nailed, then to make it look good cover it in a finish grade plywood. Then where your tank sits I would use 2x6 joists and a 2x6 rim joist. Plywood on top of those then a finish grade plywood again.
There is well over 2,000 lbs in that setup, but it's evenly distributed around all the sides. In your case the front weight will be distributed to the sides of your reptile opening.
I'd build it like typical house framing. Stud walls, plywood sheathing thats glued and nailed, then to make it look good cover it in a finish grade plywood. Then where your tank sits I would use 2x6 joists and a 2x6 rim joist. Plywood on top of those then a finish grade plywood again.