I bought a skinny orb about 2 months ago, and just cannot get her to gain wait. we started her on black worms and quickly move to shrimp and the pellet stuffed shrimp to pellets only . She knows when there is food in the tank. she goes right for it . I'm just kind of stumped. there are 2 other larger motoros in the tank but, shes very competitive at feedings. Any Ideas?