So my gf comes home with a fish that I at first thought was a lionfish then I realized her well intentioned birthday gift gets 36 inches long and eats fish. How long can I keep this fish in a 6 foot long 150 gal? How long before my clowns and mandarin become food? Rest of my fish are large but I feel like the clowns and mandarin will be prey eventually. I imagine I will have trouble rehoming this fish so I will probably have it for at least a year.