My pet has a non-ISO standard, 125 kHz microchip implanted, and I want to have it implanted with an ISO standard, 134 kHz microchip. Can I do that?
Sure you can. Both chips will function normally. If your pet is scanned with a scanner that only reads 125 kHz chips, only the 125 kHz chip will be detected. If your pet is scanned with a universal (forward- and backward-reading) scanner, it could detect one or both chips separately (see the question above this one for more information).