why are my swordtail babies so variable in size?

[Joviella]

my swordtail had her second batch of fry about 8 wks ago.Some are huge and others remain very small...can anyone tell me why this might be? her first batch were all growing at same rate.

 

[Doggfather]

could just be the amount of food each fish is getting

 

[jams.alaskan]

I've got the same thing going on. Probably just more agressive (about eating) fry get the best foods, are more thrifty.....

ALASKA

 

[guppymonkey]

Its survival of the fittest. The ones that are getting more food are growing faster then the others. In nature the smaller ones would most likely get eaten before they grew up. In an aquarium that isn't as likely to happen.

 

[HeatherSweetness]

I recently had a swordtail fry who just never grew.

It's bros and sisters were over an inch long,it just never grew and died. They do grow at various rates,and it's directly related to food. The hogs grow the fastest. I remove the biggest ones when they get about an inch so the other ones can start to grow and eat more.

 

[Paradise_Gourami]

my guppy fry are the same way

 

[juliethegr8t]

Another factor that some people aren't aware of, is that the larger fry put out chemicals that can stunt the growth of the smaller fry. This is a great reason to do frequent water changes on fry tanks. I have found that with more than weekly changes, my babies grow MUCH faster.

 

[HeatherSweetness]

Another factor that some people aren't aware of, is that the larger fry put out chemicals that can stunt the growth of the smaller fry. This is a great reason to do frequent water changes on fry tanks. I have found that with more than weekly changes, my babies grow MUCH faster.

Now that makes sense. Thanks for posting that. I didn't know that.