I have sticklebacks in my aquarium and read a study on predators ability to eat sticklebacks. Brook stickle backs only grow to a couple inches, and have enough spines to actualy deter predators. Fish can eat them but it takes longer and is more dangerous. I think they would be a very poor replacment for fatheads. Even if they did survive and add a minnow to the forage base, the only predator that will be able to eat them easily will be fish that can target larger forage.