No idea what they would have been. They can be between 1 and 2 months usually. Or very VERY stunted. My baby bettas (I bred) have color at 4-6 weeks. Moreso at 6 weeks. I also know most of mine will have a decent wide spread, rounder caudals and dad's "ooooo" face :lol:

 

With the baby bettas, I've seen people have outcomes of everything from you're typical blue/red VT to a Salamander dumbo HMPK. Many members here have found and picked up several DTs, and a couple of weeks ago when I was browsing Petco I found a baby CT and what appeared to be a very young blue marble fry(gender and tail type unknown, but because of the coloration I assume it would have turned into an HM/Delta/SD).

From what I can tell, there doesn't seem to be any 'typical' outcome for the baby bettas. It really varies, you never know what exactly you'll end up with.

However, betta fry are difficult to care for and since they're crammed in conditions that are harsh and often kill adult bettas they sometimes don't always survive once you get them home. Often times they're stunted as well, so they can take a little longer to develop.

 

If you did decide to get one, be ready to acclimate for a longer period than an adult. I also suggest perhaps getting some live foods to encourage eating (and growth). I would also clean daily and make sure the water is at 80 degrees or so. If you do decide to get one we will help you out

 

no plans to get one this side of christmas i do think next fish i get ill go for one allready developed so i know exactly what im gettin,i wouldnt want to end up with a veil tale as i allready have one

if buying these babies though or babies in general from anyone would it be ok to keep 4 or 5 of them in the same tank untill they developed their tales and you could sex them or would it be easier to keep them in single smaller tanks so u can monitor them better and make sure they all get food

 

If you're getting a group of sibling fry from a breeder, provided you kept up with frequent water changes you could probably keep them in something like a 20 gallon without much issue; just like the breeder growing them out until they start to display aggression.
However, with the baby bettas from Petco, since they've been kept separated and in rather harsh conditions and are probably already stunted, it would be best I'd think to keep them in separate setups where you can monitor them more closely. You never know if one could be sick or not.

Fry secrete a growth-inhibiting hormone that, I believe, is meant to stunt the growth of their siblings so that they are the 'stronger' one, so in either kind of setup frequent water changes are required. With the Petco baby bettas, they've already been swimming in cups that are hardly ever changed with high ammonia and this hormone, which is why its more likely for them to be stunted and also why separate setups where pristine water quality can be a little more easily maintained I think personally would be better for them.