Betta Fish: My first betta

Here is my 1st betta fish… Got it a few days ago.
Added in a cycled tank which previously had zebra danios.
Didn't add a heater as yet.
Feeding with micro pellets. Betta jsut eats a few and ignores.
It seems water flow rate is higher side. Need idea on how to reduce the flow rate.

And any overall feedback on the setup (tank is 5G, drift wood and small stones, sand as substrate, single java fern… Planning to add more plants)