when i raised my HMPK from a fry(she was a surprise after my white HMPK passed away, from a friend. mailed to me when i got some Red Cherry Shrimp from her)...
i kept Chappy in a 3 gallon with daily water changes. water at a constant 80F via adjustable heater. i didn't have a filter, but a bubbler. a few silk plants, but she LOVED the GIANT MASS of Java Moss i had in there. she was fed crushed New Life Spectrum Grow and live baby brine shrimp.
NLS Grow helps them sprout up a lot. helped with some of my smaller adults, too. xD and she LOVED chasing the BBS. i highly recommend them if you're going to raise a baby betta. they're super easy to hatch, too (i hatched mine in a picnic jug for sweet tea, with AQ salt and a light bulb and bubbler. :B)