If they are happy, healthy eating and not flashing off everything or gasping away then it is probably like Alan has suggested so just keep an eye on it.
Should be well into breeding at 1yr old, the females and males should be obvious.
blind fish should be fine, just an issue if it is genetic and you are going to breed from them you might end up with a whole heap of one eyed fish, but most fish I have seen with 1 eye have lost the other one during their life.
Any high protein food is good for conditioning fish, variety and separate the sexes, BBS is quite cheap decap is also another good option and goes a long way.