I recently bought some frozen brine shrimp. I just use a syringe to feed them, but I'm wondering how many should I be feeding?
This is the way I do it also, A bit about half the size of a match head is fine.
When I feed my bettas I give them enough food to see their bellies are slightly rounded.
I am afraid that a 10 gallon tank is not big enough for female betta sorority imo
Just my opinion, But I think a heavily planted 20g long is the minimum even then it may end in disaster.
There is all sorts of advice on keeping sororities, Such as making sure the females are sisters, Bettas are Bettas and it don't make any difference.
But a group of 4 female bettas can be kept in a 10 gal but I would not recommend this as female bettas can be very territorial and agressive, broken lines of sights with plants, wood and decor as well as hiding places are a must.
I have a female that makes my most aggressive male look like a playful kitten.
If you want to keep multiple Bettas do it in separate tanks,
My Rant and maybe a lesson.
I am also NOT a fan of most divided tanks, for a multitude of reasons, one being that if one fish gets sick they all do because they all share the same water. I have 4 tanks now and 4 sets of cleaning equipment, I learned a valuable lesson when my bettas got ICH, Result of contamination from the big tank when I got all the Tetras.
Picture this. 3 bettas, 17 Kuhli loaches, 5 Clown loaches, 2 adult BN plecs + plus 30 or so fry, 2 Mollies, 5 Platies, 60 assorted Tetras, all with ICH in heavily planted tanks with Mystery snails and shrimp, I am just grateful that raising the water temp to 32 deg c worked.