Different fry sizes

[styggian]

I'm cleaning my fry tank, so I'm getting a really good look at my babies. Some are SIGNIFICANTLY larger. I mean in the range of three times larger, maybe even more. Some look like they haven't grown at all but are otherwise still very active.

I'm sure these runts will be culled, and I know fry sizes depend on a lot of factors, including who hatched first, but is it typical for 10 day old fry to be 3-4 times the size of their siblings?

Thanks a bunch! :D

[Oldfishlady]

IMO/E...it is common for some fry to be much larger...some of it is due to hatch time since they don't hatch at the same time and in the fish world an hour or more difference in age can be a big difference.....then you have the stunting hormone that is emitted...natures way to cull-allowing the larger fry to eat the smaller fry....

Depending on how important the spawn/spawn numbers...I usually will start moving the larger fry to different grow out containers to allow the smaller fry to grow, feed...etc....without fear of being eaten....usually they will catch up in size within 30 days or so....

[styggian]

I'm not overly in need of a large spawn. I have a lot of fry, I mean at least 50+ so if it's natural culling, I don't mind. I've only found one dead fry, a tiny one, but everyone seems to be thriving despite the size difference.

I know about the stunting hormone, I'm changing about 70% water daily to keep it thinned out. Because this is a small project, and I'm new, I would prefer the biggest, healthiest fry to choose from. I'll leave the little ones for now though, since they are still doing well and not small enough to be eaten by the larger ones.

[Pewmew]

mine's 10 days today and most of them are same size, there are a few that are really big but I think I only notice 3-4 very small ones ( or maybe they are hiding and I can't see them)