Here is an idea I had when I first built my bin cage for putting a wheel or bottle on. It can be made any size and I have used the bottle as an instance. I had a bottle half the size on it and it was ideal.
With just a piece of metal I had lying around (it was an accellerator extintion for my wife in the car as she has tiny feet. lol), it was already the shape it was so I just had to bend it to form a right angle stand. I used an angle grinder to cut a slot in the top. I have not even painted it (too lazy). It cxan be screwed to a wooden surface or gaffer taped to the floor of a bin cage. Once in, it is secure. Does not even fall over when a wheel in on it and not fixed down. This one has a 3" base 5" high and 3 3/4" wide. Size can differ to what you want.
Very easy to make.
The thickness of the metal
I pinched Spidey's bottle for demonstration. lol
It will push all the way down.
Same stand
The wheel can even be bolted (with the right type of bolt, no thread near the head part) to the wire on a bin cage.
I hope this has given some people an idea of putting a bottle or wheel holder in a tank or bin cage.
I just cut mine to shape and size with an angle grinder then used a file around the edge to make it smooth.