It depends on the size of severum. If it is small about an inch or two its a goner but I don't a 4-5" lima will be able to eat a 3 inch severum because severums are tall. Don't quote me on that though because from my expience with my 7" lima, it didn't eat my JD who was only 1" tall and the JD was in the tank with the lima for 2 months or less.