A salesman snatched a tiny 2-month-old puppy from a Bronx pet shop because a clerk wouldn’t buy his fish supplies, police and workers said Tuesday.

The teacup Yorkshire terrier, who didn’t yet have a name, was playing in a 3-by-5-foot glass display case at R&K Pet Shop in West Farms on May 4 when the spurned salesman opened the latch, stuffed the dog in a green bag and bolted, according to surveillance-camera footage.

Before turning crook, the thief had tried to sell clerk Chrishelle Glover, 23, gravel and fish-tank filters, but she told him they didn’t need any — and he waited until she walked to the back of the store to get his revenge, she said.

“I said no, and I guess he got upset,” Glover said. “I heard the case unlatch. I turned around and went after him, but he was nowhere to be found.”