A thief ran into a Long Island pet store Monday morning and made off with a $2,500 Maltipoo puppy, Suffolk County police said.

The hooded robber grabbed the 3-month-old black dog from its cage in Selmer’s Pet Land on Jericho Turnpike in Huntington Station at around 10:50 a.m. before running away, cops said.

“My biggest concern is the puppy’s welfare,” Al Selmer, the store’s owner for the last 52 years, told The Post. “I would hope the person takes care of it.”

The incident was caught on video, Selmer said.

This isn’t the first time an animal snatcher has struck Selmer’s.

A Long Island mom was busted in October for swiping four bearded-dragon lizards valued at $1,100 from the store.

Anisa Escobar, 46, had walked into Selmer’s with her 14-year-old teen twin sons on Aug. 23 and used a knife to cut open the reptile enclosure. She was charged with grand larceny and endangering the welfare of a child, but the reptiles weren’t found.

“What a crazy place this is,” Selmer joked. “I think it shows the temperament of the times,” he added more seriously. “That it seems to be something people just do… They say ‘I want it,’ take it and goodbye.”

Suffolk cops ask that anyone who comes across the alleged thief — who is in his 20s and has a mustache or goatee — call the Second Squad at 631-854-8252.