If you must get a Lab with the Fronts, don't get one that is twice as big. It should be near the same size or smaller. They grow much quicker than the Fronts. So, they will be a little more dominant in the tank until the Fronts get bigger. But, you need to have more than 2 Fronts in the tank anyway. It should be six, but in that tank, 4 might be okay for awhile. One will dominate over the other and chase it all day if you only have two. You need more in the tank to diffuse aggression. True, they are not as aggressive as other cichlids, but they still do show aggression. The Labs are much more aggressive eaters and they are more active in the tank, but the Fronts will eventually get less shy.