Swordtails are live bearers originally from Mexico and nearby. Goldfish are a form of carp like fish from Eurasia that lay eggs. Swords need temperatures in the high 50ðs or more to stay alive while goldfish can handle winter water temperatures where the ice freezes for many months.

I'm pretty certain goldfish and swordtails can not interbreed. Swordtails I believe are livebearers meaning they give birth to small fish. Goldfish are egg layers.

If your really curious take a few out and look at them in a tank to get a better look.

rsingley,
I pulled out several this morning to get a good look, that's why I started this thread.
They are bigger than the adult swordtails, but have black fins and/or swordtails, with a lovely golden color. Maybe I've discovered a new mutation; Giant Golden Swordtails. (tm)

I put them in a different pond so I can see what happens as they mature.

thanks,
Lee

Did you take any pictures? I would love to see your Giant Golden Swordtails.

Hi
Swords/platies can't cross with goldfish due to an entirely different method of reproduction. They are livebearers while GF are egg layers.
I raised platies swords in my pools for many years until the deep freeze of 09 lol. Last i heard there are at least 200 color /fin and size morphs They hybridize between the families of platies /swordtails easily, resulting in an incredible variation due to selective breeding.
As to size they range from about an inch to around 6 inches ,maybe more?? a whole rainbow of colors and fin forms. Last I heard on the epitome of .swordtail breeding
was "Red eyed /red, hi fin .double sword ,lyre tailed ." Don't even remotely resemble their wild ancestors lol
i raised "Red wag" meaning red bodies with black fins
but ended up with over 30 color and fin forms over the years.
If interested in setting a strain you'll need some knowledge of genetics as well as a lot of control of parentage . My particular goal was a set strain of" Red jet"
meaning half the body was black, half red but the closest I got was polka dot though i did get a nice strain of " red wag" without any trace of orange usually called "Red velvet"
As to the yellows /gold/ orange varieties have no idea where the standard is today.There are books available on the subject gary

Pictures? what a great idea! Wish I'd thought of it. I'll try in a few days, when they've forgotten the horrors of the net.

I talked to the person who gave me the swordtails a year ago. SHE also got a few giant goldens (there goes my fortune for a new kind of fish!).