Translation:You are like a fish out of water.
I agree - however I don't think this example is really outlandish. Its meaning is immediately clear even if it wasn't idiomatic.
In contrast, the idiom "hands down" is a little stranger and wouldn't translate well word-for-word in Greek. In French "hands down" translates to "le doigts dans le nez" (fingers in the nose")!!
Interesting, I have never heard this idiom and I use English a lot. So does it mean that you're out of your safe environment? In Czech we use 'He is lika a fish IN the water', meaning the opposite: That he fits in well, is very skilled, experienced in sth. I wonder whether this phrase exists in English or Greek as well...
No, "like a fish out of water" is a fixed expression trying to change it just makes it sound unnatural. Actually, we most often use "out of water" never "outsidee". "Take the carrots out of the water and let them dry." "Take the shirts out of the water." etc you'd never say outside. Don't push unnatural usage.