I assume that you are referring to the med to large type and not the small? Either way I wouldn't mix them with any other species, especially if they look similar. I would do a species only tank with LOTS of good hiding spots (I would recommend PVC) and keep a hospital tank ready just in case. Good tight lids are a must, this fish is fast and can exit the water very quickly.
The larger Pikes can get really big at 20" +. Mediums around 8" or so.
They will team up and eliminate the week. A friend of mine tried for 2 years to get a mated pair in a 150 and all he could do was scoop out the bodies till the last couple was standing. He finally had success. But even then without the hiding spots the male would have killed the female if she had no where to go.
They are just as predatory if not more so than Jaguars.
But a very cool and interesting fish.