also look at crypts...would look nice in that tank and my betta LOVES his crypt...it is rather large (they grow pretty slow but if you keep it for the long haul are amazing and very undemanding plants)...my boy uses it like a reclining chair....lays sideways on it like he is really napping! would look fab in the foreground...and i agree with Honeythorn that camboba would be GREAT to fill in the gaps in the middle...bettas realllly like lots of plants IME!
cheers. looks like a great start and im sure he's thrilled in there... but you cant really have too many plants...so beneficial to all involved!
That's Elodia. When it starts to trail along the surface and block light, snip it off just below the water line. It also puts off side roots , in that case you pinch the plant off just below those roots, strip the bottom few leaves around them, and plant it.
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nice