Can we put 3-4 female bettas of different age in same tank?

[Aniket]

I have 3 females. One is 1.5 year old and other two are 6-7 month old, i brought them from different tanks. I kept young females in one tank but one of them was flaring at other so seperated them.

 

[NickAu]

Maybe.
Flaring and chasing is normal especially in a new sorority, the girls need to establish a pecking order, as long as its not excessive, so is the occasional nipped fin, But at the end of the day only the Bettas can decide if they want to live with each other.

I have added new mature bettas to my existing betta sorority and sometimes it worked and sometimes it didnt work, I have added young bettas to my sorority tank with the same results.

These are my girls in their old tank, they are now in a 6 foot 100 gallon heavily planted tank. the one in my signature

PS
The new girl is the one with the yes you guessed it ripped fins, took em about a week to really settle down.

 

[Colin_T]

Rearrange the tank and move things about before putting them all in together. Breaking up the old territories means they all have to start from new and gives the newer fish more chance of living.

 

[NickAu]

Rearrange the tank and move things about

Not as easy as you think in a tank's like mine without ripping up plants and as you can see I hate pruning.

 

[Colin_T]

In a heavily planted tank, take all the fish out and put them in a different tank for 24 hours, then put all the fish back in together. Or just add the new fish and hope for the best

I'm amazed the fish can even see each other in your tanks Nick. They swim around and wow, hi, how you going, haven't seen you in ages, where you been hanging out? just behind this plant, or was it this one, nope maybe that one

 

[NickAu]

I'm amazed the fish can even see each other in your tanks Nick. They swim around and wow, hi, how you going, haven't seen you in ages, where you been hanging out? just behind this plant, or was it this one, nope maybe that one

Yes its why a heavily planted tank like that is best for a sorority.