Also, a 46 gallon is too small for most turtles. You might be able to get a hatchling and grow it out in the tank with little to no fish loss, but it will probably require a bigger tank after a year or two, maybe shorter or longer depending on the species. I've seen very large community setups with turtles and fish, but the fish were either very fast or large. One example was a tank the Columbus Zoo used to have with 2 huge Aussie Lungs, a couple hundred Boseman's rainbows, and a pair of pink-bellied short-neck turtles (and I believe also a carpet python in the land section up top). It was a very cool setup, but only possible in a room sized enclosure (and I'm sure even then they lost a rainbow here and there)