Tanks with tunnels... Why dont fish swim over/under the tunnels?

[Gadzooks]

Despite these tanks being large, the fish seem to actually have less room to swim. They seem to be stuck on one side or the other, unable to swim over/under the tunnel that your visitors can walk through.

Kinda disappointing.

[76561198356019466]

I saw that and worried but I noticed that they seem to "transfer" to the other side.
I'll watch one for a while, go to another section of the aquarium for some other work, check back, and he'll magically be on the other side.

It's Magic! :P

[Flishster]

So they used to be able to briefly when Freshwater Frenzy was released, however this also allowed bottom dwellers (starfish, lobster, etc.) to teleport up on top of the tunnel and it looked super bad.

[c_Alien]

Same with certain deko objects, like the net. Fish seem not to be able to move through it.
Might be a way to save smaller fish from being eaten until they grow bigger.

Fish in tunnel tanks can teleport, but do so rarely. As far as I have witnessed.