Grow Tank Vs Natural Selection
On this forum I've read about people leaving fry (I'm talking mollies here) in the tank, letting nature take its course. I've also read about people putting fry in grow tanks. I've tried both methods and here are MY (as opposed to other people's ideas):
If you leave fry in a tank and let natural selection take its course, will you have stronger, smarter fish, or smaller stunted fish, wiley though they may be?
I've found it far preferable to remove the fry to a grow tank because they grow larger and healthier. The fry have more room to swim and develop their bodies and they don't have to compete with larger fish in order to get proper nourishment.
The fry I left in the tank with the adults did NOT grow into large, beautiful fish on the whole. They were smaller and not quite as pretty.
I tried another experiment where I took some fry I had left in the adult tank for several weeks, moved them to a grow tank, then watched. The fry did NOT make up for lost time. They stayed small and runty-looking, and I tend to over feed. On the other hand, the fry I removed in the first week of life are big, fat, and healthy, what a fish should look like.
I've concluded that natural selection is fine and it does cut down on the number of fry that make it to adulthood. However, those that do survive are not necessarily the best-looking fish in the tank. Therefore, I've further concluded a grow tank is best for fry you may want to keep.
Naturally, this is just MY opinion and there are exceptions to every rule - I even have a couple, but on the whole a grow tank seems a better idea.