SAL stopped eating and just floats

Got my first 2" SAL a week ago. He was eating bloodworm or two for the first 7 days. In the last 4 days, he just stays floating at the top where before he would be on the bottom. Now he has stopped eating as of 2 days ago. He would take in a bloodworm, and look like he is eating it. Eventually, he just spits it out. He's in a breeder box.

Anything I can do to get him to start eating again? Why is he just mouthing the bloodworm? Or is this normal for a young SAL? What about the floating is that normal?

Water parameters: Ammonia and nitrites =0ppm, nitrates less than 20ppm, ph=7.8, water temp = 78F

What's the dosage of epsom salt? Do I put it in the main tank or a bath? If a bath for how long?

He didn't make it. I found him this morning and he looked like he rammed into the side of the breeder and broke his neck since his body was at a 90 degree angle.

I tried the Epsom salt bath, and it didn't help. He was releasing bubbles as he swam while in the bath but was not sinking. I suspected something else was wrong. I found information on wetwebmedia where someone had a batch of SALs for study that floated, and they determined it to be a bacterial infection that caused them to float. I tried a treatment of Kanaplex for 48 hours to treat for gram negative bacteria since I had that readily on hand but there was no change. The only thing I didn't get to try was Erythromycin.