Yes. Bent spine is one result of nitrate poisoning. It's a possibility.
Could well be but it could also be as a result of a vitamin deficency either way I dont think he has much longer to live , Priscilla your saying he likes to get to a spot where he doesnt get washed around.
Siamese fighters like a still surface area he is a labyrinth fish who lives on a diet of crustations insects and dried foods and is best kept in a species tank he has an auxilary breathing organ which means he can be kept in relitively small aquariums males shouldnt be kept together in the same tank as they will fight and he should be kept with only two females
Provide plenty of plants for the females to hide in when not mating and a still surface area for a bubble nest to be made when breeding, they create a bubble nest lay their eggs then blow into the nest from bellow to keep the nest oxigenated . .
He should have a tank temperature of around about 26-28c, plus have a ready supply of snails to eat .
I dont think your going to turn this guy around sadly
If you go to their country of origin you'll find they are kept in jam jars and they are bred for fighting each other in matches where money is betted on the outcome of the fight when they are put togther.
Dave