Both are same size about 9-10 inch.tank size is 5 feet long (for now).will move them to pond when they are bigger . There are no other fish in the tank.
They’ll be territorial towards each other but if there’s enough room should be ok. You should move them to the pond now as they are pushing the limits of your tank size currently. Moving them when they are bigger than 12-18 inches can be difficult and more stressful to them.
I worked as an importer and have dealt with this kind of stuff on numerous occasions, they'll be fine. Just make sure they are around the same size and make sure they aren't beating eachother up too bad