Platys

[coyemuse]

How big do platys tend to get... I was told 2 inches, but the ones I have are almost the size of my swords... and my swords are about 3-4 inches

 

[Neptune54]

There are two types of platies- variatus and southern (I think ). Variatus platies are bigger than the other type, so that's probably what you have.

 

[coyemuse]

Alright. I just know they were like 1/2 an inch long when I got them a month a go... and it seems like really quick growth in such a short time

 

[Neptune54]

With a large tank and good food, I wouldn't be surprised at a fast growth rate like yours.

 

[snazy]

I have a huge female platy. Not only she is long but she is fat/wide too. She is way bigger than my other female platy and female swordtail. I guess some of them grow quite big.

 

[Akasha72]

I have a platy that's a good 7cm. She was bought as a red wagtail but now she's fully grown and I have other platies too I can see there is a difference in her. My Dad has kept fish for years and we've now both agreed she's more likely to be a platy/molly cross. The difference is around her face and nose area. Her nose is more pointed like a molly but in every other way she's a red wagtail platy who's too big for her boots in more ways than one (she's the tank boss and bully)

Platies and mollies can interbreed (or so I've read) so if they are on the big side don't rule out cross breeding.

The fully grown size of a platy is around 5cm

 

[OldMan47]

Platies and swordtails that we see at the LFS are always crosses between platies and swordtails. There is no easy way to predict the biggest or smallest that you will see of either one. Don't forget that standard length, listed as SL most places, measurement never includes the tail itself. I includes the fish from its nose to it caudal peduncle only. I have kept many wild type Xiphophorus. In those the adult size is far easier to predict because each one is actually a specific species, not some odd mix like we get with LFS fish. My X. alvarezi, upland swordtails, are still young but are about 5 cm SL right now. My X. helleri grew to about 10cm SL before I sold them off. My X. nezacoyotl (I bet I spelled that wrong), nezzy swords are staying fairly small at around 6cm SL even as adults. Each is a distinct species that is called swordtails but all 3 are very different fish. The nezzies are known for having extremely long swords, and mine are no exception. Although the fish's body is fairly short at only about 6 cm, the tails on them are closer to 8 cm. The helleri is one of the ancestors of most pet shop swordtails. It has a much larger body but a relatively short tail compared to its nezzy cousin.
If you go to the reference materials, you will find not 2 or 3 but dozens of swordtail species and of platy species. Variatus is a particular species but the stuff you see called that at your LFS is a mix just like all the rest of their Xiphophorus stock. A true variatus is only ever found being kept by specialists, not at the LFS. I have never seen one in person but I have had platies and swords in my tanks for over 50 years.