Wall mount tanks and In-Wall aquariums are similar but very different. Let’s examine. Both look cool, have a nice viewing area, have light, filter and heater but that’s where the similarities end. An In-wall aquarium gets built into your wall while a wall mount hangs more or less like a picture. A fish tank built in can be much larger meaning much larger and more fish. In fact since a wall mount hangs it does not have enough support to hold much water and therefore it’s extremely limited. It may look cool but ultimately not be satisfying with your fish options.
Another major difference is the finished look or wow factor. A built in tank with the front flush with the wall looks awesome! Now finish both sides and peer through the aquarium between rooms. This is the ultimate fish tank. You can think of a wall mount as a toy compared to a flush see through in-wall tank.
Of course the wall mounts have some pros. It’s much easier to install. Typically you might be adding some screws or plywood to the wall and an electrical outlet but not much else. A built in tank requires more labor, materials and know-how. A typical built-in tank can take 2 days compared to 2 hours. A built-in might cost more in the end but if you’re doing the work yourself it’s not much different.
Obviously I am recommending a built-in tank. I have one, I love it! But I am handy and have the experience to do all the work myself. If you do not have the know-how or can’t be bothered to go through the work than an unsatisfying wall mount might be for you.