hello hello new to betta breeding

[itsjason]

Hi im jason from melbourne, just started to really getting into nitry gritty of betta fish.  I have a cold tank 140 community tank with shubunkins etc and a few bettas which enjoyed the currents and interaction.

Ive got a hold of some 4bays tanks and fry tank.  I had a successfull hatch with hundreda of fry.  Unfortunately the tank had a live plant and got really murky and i added a couple litres of fresh water treated but all the fry ended up dead apart from 1.  There were a few hunded and only 2 fry were growing alot more excelled then all the rest.

I was feeding them powdered betta food,  and also frozen blocks for betta and bryne shrimp.  I could get a hold of any liquid food or anything else.

Any ideas how it all went wrong?