Personally I wouldn't do corys. I feel like a mid or upper level dither would be better as the parents will hopefully be patrolling the bottom, female guarding eggs. Are you going to remove the male once they've spawned? Regani are pretty gentle pikes but he still might kill her believe it or not. I guess if you have the right dithers, violence could be avoided all together. I think a male dwarf pike could do some serious damage to corys. Get something faster that will swim the length of the tank...