He(she?) will have his new tank approx 60 at the end of the summer, and he will be keeping company by then with the Betta and gourami fry culls (AKA "it was there yesterday...").
Heh, I know in my excitement, I sound like I want to plop something in tomorrow.....
I am mostly wondering about cleaning helpers and and a 3-4 non bite-sized peaceful fish. I'd rather there be nothing than have something bother him. He was traded for to be a culling machine. He will have a beautiful buffet of unnamed anabantids. And will stay looking the same cute look therefore the kids can't wait instead of "oh..nooo"
I am one who likes planning ahead. Getting fish for Christmas was quite a shock to my system!

And I am not familiar with knifefish at all.
edit: Tank by person doing daughter's tanks. 16x44x24 Acrylic