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Livebearers Questions and comments about livebearers

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Fortyanna Fortyanna is offline
Join Date: Apr 2008
Posts: 49
Default 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.
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Neoblaze550 Neoblaze550 is offline
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Join Date: Sep 2007
Location: Lexington,Ky
Posts: 909
Default Re: Grow Tank Vs Natural Selection

I tried something similar with Kribensis fry. I put half in the community tank and left the others in the grow out tank. I noticed that only one or two kribs will grow in the grow out tank, but in the community tank the fry seem to grow at the same pace.

I also raised an endler fry with the kribs. He is the most agressive and territorial endler I have ever seen. He even chases the kribs away from his females and food.
55 gallon: 4 angels, 2 discus, Amazon tetras, corys, 1 sml flag cichlid, Farlowellas.
40 gallon: 2 Gold Severum, 2 Butterfly fish, krib fry, 1 female convict, 1 BP.
29 gallon: 3 Kribs, 3 Keyholes, 1 Butterfly cichlid, Krib fry
10 gallon: Krib fry!!!
8 gallon: 1 Male betta
Neoblaze (Aka Cole )
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Fortyanna Fortyanna is offline
Join Date: Apr 2008
Posts: 49
Default Re: Grow Tank Vs Natural Selection

Interesting that we came up with 2 different results, thank you. I'm not familiar with kribensis, will have to check them out.

Right now I'm looking at 8 black molly fry about 3 months old (left in tank for quite a while before I moved them) and the 2-week-old fry I just put in there. Oddly, they're almost the same size despite my feeding them well.

Any other opinions or experiences with this?

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