Plenty of people have including myself. It all depends on the temperament of the individual turtle. Mine is fine with fish and hates rays. Others have had no issues with this combo.
Just saw a thread less than a month ago of someones turtle tearing up a bunch of rays in a new tank. Its your pets but both are expensive and rare enough I wouldnt risk it.
Turtles and fish don't mix because turtles eat fish
A lot of people say it worked for sometime this is because FRT diet changes they mainly eat veg when small but once the get larger the they start eating fish
This is a pic i posted a few weeks back. This was done by a Chinese soft shell that i kept from a small 3" to it got to around 1 foot across the shell. It was a great turtle that we all loved dearly. She would hand feed an i found it very hard to believe it would ever do any damage to a fish. In the end i sold her as everyone was saying it was a bad idea to mix with rays and other fish. Glad i did. With in a month of the new owner getting her he put her with a ray. This is what the turtle done.
i keep my 5" carapace FRT with 7" disc leo pair & 6" pearl pair, also an 8" Super Red, 2 Red Severums & 2 Tinfoils.
noticed just yesterday dat the tail tip of 1 of the pearl has been chewed up!!! it was just a couple of months back that i had to give away my 4 beautiful leporinus fish coz i saw them chew up both the leo's tail... dont ask me why but taking this past experience, i just went ahead & concluded that this new damage must've been made by the tinfoils!!!
i watched the tank closely & within a few mins realized that the tinfoils were just imprudently swimming about the tank, but it was the FRT that was slowly sneaking up on the Pearl & nipping bits of the tail off!!!
i immediately moved him to a presently empty feeder fish tank & have informed my LFS guy that i wanna give the FRT away ASAP!!!
u make ur call, either the FRT or the Rays!!! Very very very lucky if u get to keep both in the same tank!!!
p.s.
i think it was T1karmann that told me in 1 of the earlier threads that FRT with rays is a ticking bomb!!! i decided to take the risk & now i'm suffering watching my pearl heal!!!