Plath fry runt

[Bre7337]

So I have 4 Mickey Mouse platy fry that are almost 4 months old. 1 is large, 2 are average/medium size, and one is pretty small. The small one is also more of a long oval without the curves of the others.. kinda like a rectangle. He’s a good swimmer and seems to be eating fine, but I noticed he does rest on the rocks more than others in addition to his different shape/size. Does anyone have any ideas as to why he might be so small and shaped different?

I say he because this fish seems to be developing male characteristics. I also heard that in terms of growth rate, females blow up first, followed by regular size males, and then smaller males, is there any merit to that? This one seems to have peaked at his 2 month size.

 

[coralbandit]

There are two sides to every coin.
At first appearance some may see a runt.
A fish that is smaller and less dominant then the others.
Some believe when it comes to swordtails which have been bred with platies for a long time ,that the slow growing male will become the alpha and live longer...
It is also believed that the larger male now may be excreting GHI [Growth Inhibiting Hormones] to keep his competition from rivaling him...
I have moved alpha males out of a colony of sword tails only to see two 'would be females ' over 8 months old turn male in less then a month.
Can you separate the males?
With a 3-5 year life span if I had the room I might hold on to him for a year and see.

 

[Bre7337]

I don’t have a spare tank but I could maybe divide the fry tank for now, but I think they’re a bit young to determine make from female completely. I definitely plan on keeping them all at least for now, I’m just not sure if I should be concerned about this particular one being so small.

 

[V227]

It seems that when a juvenile grouping of the same species is introduced into a tank, there is usually one that doesn't progress, or runts. This is especially true with New World cichlids. As the members of the school grow watch the noted fishes eye proportion in relation to his body. If the eyes are abnormally large compared to the body, likely a runt or dwarf.