in most cases you're totally right, but my turtles are all sliders and are monsters (in the best way). they eat....EVERYTHING. they've eaten every plant i've put in there, include emergent ones like papyrus. any other living thing that isn't a turtle, is eventually food. More importantly the cats wouldn't be able to survive being frozen like the gar and turtles can. No rays so that's easy to deal withJust FYI, you can keep the turtles in the same pond as the cats,rays, and Gar. I made a simple wall of plexi glass that is 18" hignh that I haver around my pond to make sure my arapaima doesn't jump out. I haven't noticed my gars ever jump higher than an inch or 2. One of my gars is 14 years old and 4+nfeet long. The other is 5 years old 3+ feet. I think they are super easy to keep. I have had problems with arowanas jumping out..... sucks to find them on the ground. Good Luck and have FUN!