I don't think we have them in AustraliaIt’s a Gambusia sexradiata
Agree with Colin, I have a Botia kubotai that I bought and dont knowIt's not a native fish, it's introduced.
All Gambusia species are considered Noxious right across Australia. When something is considered a noxious species you are not allowed to keep, breed or sell that species, and any that you catch, find or collect, must be destroyed where you find them.
As for your fish, you can keep it but don't tell anyone you have it and don't get rid of it. Just let it live out its life in a tank with other fish that can tolerate it.