Hi,
I have a batch of 5 week old copper fry (HM father,mother close to it) and was wondering when I might see any HM potential. I'm just starting to see some branching on the larger fry (about 3/4"). What are some things I should look for? Is it better to separate potential HMs?

TIA!

You can leave them together until they start "bickering", then you need to "jar" them separately to avoid fin damage.

As far as to when they would start showing HM potential, that all depends on feeding, religious water changes, and the betta themselves because they develop at different rates even within the same spawn. I would look for the ones with the best caudle spread. Then keep them "carded" so they can't see their neighbor. Remove the cards daily for an hour or so and the males will usually flare their butts off at each other. :LOL: Letting them "exercise" or stretch their fins like this can mean the difference in their developing into a HM or just a SD. Leave them carded between sessions so they don't get used to each other and stop flaring. I would do this with all of the males actually as it will improve the spread on all of them.

Hope this helps!! :D

You can start looking at the aged of 2 1/2 to 3 1/2 months old. Pay more attention at that period. Usually the first male you saw in the tank is usually not that good when they get adulthood. Too fast growth in my opinion. They look very good the first. The best is to sellect the middle group males sellection. The last batch males usually are smaller and not good to breed. ;) They can be spectacular sometimes.
It will be good to sapperating the bigger and the smaller into two tanks. Then you can see the smaller group will peak up fast. Usually the bigger eat like pigs and the smaller one hardly can get the food. :D