New Axie is skinny-help

[Thomomom]

My new axie is about 4 inches long and skinny, just got him from pet shop. he keeps blowing water to make the sand in the bottom of tank go into a mini cloud. is it normal and what does it mean? He looks like he has hikups =]

 

[Jennewt]

The sand blowing is some sort of gulping, but I don't know why he's doing it. Is he eating (and what is he eating)?