Your tank seems to have enough plants..maybe group them together a little more to create kind of an inlet for your betta or other fish to hide and get a better cave for your betta..the deco you have is ok but not really a place your betta can hide. cory catfish are great. ive also seen tetras but thats an iffy one because they can nip at your betta's fins or vice versa. snails are ok but produce a