i would like to get some female rustys to go in a spare tank with my male but i want to put some yellow lab fry in there also so they dont have to grow out in a 14 gallon. Would they get killed by the rustys while they are trying to breed. How big should the fry be before i can safely put them in with the rusty ? rusty is approx 3 inches and the spare tank is 50 gallons