Neptune does not find interest in flaring at his reflection (or at other bettas) or making bubble nests. To try and entertain him I wave my finger across the front of his bowl for him to follow and chase him around his bowl with my finger or a net. I assume it doesn't scare him since he doesn't hide in his tree trunk when I do. And continues to follow me around afterwards :)
I taught him to jump for the food on my finger, perhaps I should find a plastic hoop and see if I can get him to swim through it...
I put my finger on the side of the tank and have him follow it around. My betta chases my last two neon tetras whenever they get too close to him :P I also put new and interesting items in front of his tank every day, like a shiny figurine, a comic book, pencil sharpener, my kitten, just random things. xD He reacts differently to each :)
My Betta likes to play tag with my Shrimp. He chases them around the tank, then he turns around and they chase him. It's fun to watch.
He also likes to follow my finger around the glass, but if I put my finger in the water he just stares at it and when I move it he runs away.
Today I was trying to get a good look at his fins looking for Fin Rot, velvet or other diseases ( I do it every week or two just to make sure) and was using a flashlight. He started chasing the light around the tank like a cat does.
I'll drop in a random objects in, like the old (clean) lid from a fish foot container, etc. Shamum is hilarious. He flares his fins just a bit, gets all sideways like a cat and floats backwards away from the object. After about 5 or 10 seconds he's totally checking it out. If it's something big enough for him to swim into he will.
I noticed last night, in an attempt to get him to pellets ( I drop him one or two daily just to keep trying), I dropped in about 5 pellets on accident, so in an attempt to retreive the extras before they sank I stuck my finger in to pull them to the edge of the tank. Shamus attacked the one pellet I was going for as if I were another fish trying to take his meal.
Lololol at the taxes thing.
I got mine a tiny bubble stone, he plays in the bubbles and likes to nip at them. I also show him videos some times of random types of fish or female bettas (he never flares and sits there, dumbfounded). I also like to put interesting, colorful things by his tank so he looks at them, which is great for getting a good look at him and taking pics while hes preoccupied :3 <3