During surgery, vets found a puncture in Riko's eyeball and his eye had to be removed.
Judging by the bullet extracted, they were told the weapon was most likely a .22 calibre or larger.
Riko's owners have started a Givealittle page to help pay for the vet bills.
SPCA and police are investigating the incident.
Senior Sergeant Pete Stills said a person had been spoken to in relation to the shooting but no one has been charged yet.
SPCA spokeswoman Jessie Gilchrist said four jobs of this nature have been reported since December. These were in Waiau, Springston, Belfast and Prebbleton.
"There were three jobs in Prebbleton reported in the last three years. The locations of these incidents could possibly suggest that there is a link."
Gilchrist said for cases like this, it is typically very difficult to gather enough evidence to prove who the offender is.
Meanwhile, Adam Leatherhead said his family, including his two daughters, age 11 and 13-years-old, are still impacted by the loss of their cat, Midnight, after he was shot on two separate occasions.
In January 2017, two-year-old Midnight was shot with a .22 calibre bullet and his back left leg was amputated
Almost a year later, Midnight was shot again, this time in his front left leg. He had to be put down.
"I don't think the kids ever got over it . . . it's had a real impact on us. It's exceptionally upsetting," said Leatherhead.
The vet bills as a result of the shootings were close to $2000.
The family live less than five minutes from Hayton and Petronelli.
Also living nearby is Kirsty Sewell and her family, whose cat Kylo was shot in November.
The two-year-old had a "major fracture" after being shot in the leg.
"He's still got his leg and he is absolutely fine. It cost $4000 in vet bills though."
"It's horrible, I wish they would catch whoever it is. I'd like them to pay for the vet bills, as a minimum. Because all up there's at least $7000, that might stop them," said Sewell.
- Star.kiwi