It seems someone somewhere is preying upon the gullibillity and ignorance of the fish buying public and selling something that is not a Koi as a Koi. (Officially/Taxonomicaly there is no such thing as a Koi Swordfish). Koi (Cyprinus carpio) is not a description it is a species. They are cold water egg layers that can grow to around 4 or 5 feet long. Koi are members of the goldfish family. Guppies (Poecilia reticulata) are tropical livebearing fish and grow to a maximum of 2 inches. These two species obviously can not cross breed. It is possible that (In America) the common Swordtail Guppy is now being promoted/sold as a Koi Swordtail. If this is the case then yes all of the many different colour types and fin types of guppy (Poecilia reticulata) can and will readily breed with one another because they are the same species.
if you mean "breed" not "bread" then yes they can
They can with mosquito fish.
Simple answer is yes. Guppies mate and produce young under almost any reasonable conditions. The presence of other fish will not bother them at all provided the other fish are not predators and the guppies under pressure for survival.
Oscars are the breed of fish that mate the most. However, guppies and trigger fish also mate much more than other breeds of fish.
They can be in a community of other tropical fish of the same size.
No, they are to different types of fish and it would be impossible to breed them.
Guppies can mate in a community tank of tropical fish around their size. Be sure to add lots of live plants!
Fish that have long, wavy fins should not be put with guppies, because guppies will nibble their long fins. Also, many bigger fish will eat guppies. Keep a separate tank with guppies and a few "cleaner" fish, which do not harm guppies.
Any fish may fight/bite if they are in cramped conditions and/or poorly fed. Guppies are not regarded as fighters but may sometimes do a bit of fin nipping of any fish with long flowing fins including other guppies and Bettas.
most fish will even guppies will eat other guppies it is a risk all ways
Guppies can live very happily with heaps of other species of tropical fish
Adult guppies eat their own babies, and fish like tuna eat guppies.
I doubt that they can breed, a lot more depends on if two fish can breed than just their size, as far as I know guppies can only breed with other guppies.
yes