I've had a tough time keeping my betta frye alive - through three separate cycles they've only made it to about 2 weeks. I've changed their water weekly (even tried using only pond water in the changeovers), tried different betta baby foods such as "Hikari's First Bites", cooked egg yolk diluted w/water, frozen brine shrimp (unfrozen when I feed it to them), I've tried grinding up the little Hikari balls, grinding up freeze dried blood worms, grinding up betta fish flakes. I keep the water consistently warm, but not too warm. My grown bettas are fine, I just can't get the babies to grow past two weeks. It looks like they gradually just waste away. Any suggestions?