We have both the 3 and 9 spined sticklebacks here in the US. The roach is closely related to our golden shiner, so closely they readily hybridize where the roach has been introduced to North America. Your perch and our perch are also extremely closely related, however I am unaware of any European perch being introduced into North America. The ruffe was accidentally introduced into our Great Lakes and is now creating a mess.
