I'm not sure how or why they develop the twisted spine, I had a 1 foot bichir with a twisted spine and he ate and lived fine until it got caught in my powerhead (talk about a huge bummer) as long as it eats and can get away from attackers it should be fine. I've also had many cichlids that i've bred come out disfigured, pretty interesting...I have a hybrid that has a smushed face and its jaw is sideways yet still it eats, swims and fights like a normal cichlid haha
"Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering."