Mirror inside tank

I only just registered days ago that the tank inside appears like it has mirrors from the inside looking out so the fish can only see their own surroundings, but from the outside, we can see through every layer. I have so many questions now. I haven't yet changed water to see if its the same when water level is low, or if its the water that creates this effect, mainly though..

Howcome the fish seem like they can see me as I approach for feeding time?

im certain you all know this already... But here are photos anyway. From the front you can see through the tank to the wall behind...



But from here you can see the reflection of the heater and inside aquarium.
Here you can see the reflection of anubias plant.


And here straight through to the lounge door behind aquarium.

I'm not the best with physics, I'm a little confused at what the fish see and my partner and I are perplexed at whether its a special glass thing or its the water illusion....

It is an optical illusion caused by the glass and water

It's definitely the optical illusion caused by the light reflecting with the glass and water. Try turning off all the room lights and just looking through the side glass. Normal glass, right? You can see through it into the tank just fine.

The tanks are made with normal glass, no mirror layers or anything.

I concur. How the fish see through the glass is not how we see things.

You should use a background on a fish tank. Something as simple as plain black construction paper that is not glossy works very well taped on the outside of the back glass wall. It really does make a difference to the fish.

Another funny thing with water is refraction. Don't know if this is true with tanks as the light tends to always be straight on but, in nature it is different. Ever been by a stream or river and seen a fish in the water? That fish, and other stuff, isn't exactly where it seems. Water 'bends' light making things seem in a bit of a different location than they really are.

Many, many years ago I did a bit of archery fishing. Unless high noon, with the sun directly overhead, you would probably miss the fish if directly aimed. You had to look at where the sun was and adjust for the refraction of light to have a decent chance.

Water is strange stuff. For instance I have a fake tree trunk in my tank. If I look at the directly from the front or side there is one trunk. If I look from a corner there are two trunks.

Just to show how odd is water it is the only compound that increases in volume when, both, a gas or solid. To my knowledge no other substance does this. Let's just take iron. A solid chunk has the least volume. Melt it and the volume increases. Get it hot enough to go to a gaseous state and the volume increases even more. Water is the only thing I've ever seen that does not follow this pattern. Water, as a liquid, is the base. Unlike anything else water will increase in volume in both other states. As a solid (ice) and gas (steam) both have more volume than water as a liquid. Water is possibly one of the oddest and most interesting compounds in nature.

Your post reminds me of one of Sir David Attenborough's earlier series, in an episode on fresh water. Water is the only substance on earth apart from mercury that remains liquid at normal temperatures and pressures. And it is the only substance that is less dense in its solid form than in its liquid form--and a jolly good thing, or the oceans would long ago have frozen solid from the bottom up. Water is "the universal solvent" because it is capable of dissolving more substances than any other liquid, which is why adding substances to the tank water is so dangerous if they can diffuse across the cell membranes of a fish along with the water.