I was messing around with Google and decided to look at all the stuff they have available to you. (BTW I am in no way affiliated with Google or anything.)
I found SketchUp, a free
3d drawing program which is actually kind of fun to mess around with. Considering I can't draw I managed to make a 3d... thing
I wanted to share the link with people who could draw, just in case anyone wanted to try it. 3d Betta's would be cool. :)
It is pretty easy to use, is free, and has tutorials. I don't know if you need to sign up with a google account or not though in order to download it. I already had one, so I guess you would need to see.
Anyways, hope you all have fun, and Best Wishes!