You'll get multicolors, likely metallic blue-greens with lots of red wash. Longfin is dominant over plakat, and crowntail is partial dominant, so they'll look most like veiltail combtails.
I agree with 1f2f. Crossing tails and using fish of a mysterious lineage aren't a good base for a breeding program. Start with fish that will get you closer to what you want to achieve to begin with and you'll save a lot of time, money, effort, and fish's lives.
Last edited by Adastra; 08-16-2010 at 12:24 PM.