With so many hybrids in the hobby now between Xiphophorus maculatus, X. helleri and X. variatus you can buy some very beautiful fish but what has been lost is the uniqueness of each species. Xiphophorus maculatus, the platy has always been a short full body fish with that has been lined bred to produce some breath taking colors. Xiphophorus variatus was always in my estimation a longer body platy with also some brilliant colors. Xiphophorus helleri, the Swordtail was and is the larger of the trio with the males having a swordtail about half the length of the body. But, one is hard pressed to be able to go into any pet store and find a “helleri” with anything more than a pitiful scaled back swordtail approaching maybe a third of its body length. You can now find “maculatus and variatus” with small swords. All beautiful, but all not quite the same as the originals.
Thus, brings me to the title. Xiphophorus montezumae , Montezuma Swordtail is truly a striking fish. The swordtail on the fish more than makes up for the lack of brilliant color. The fish is an over all olive with a dark brown zig-zag stripe along the lateral line, with the flanks being either spotted in black or in same fish the body behind the dorsal fin is almost all black. The dorsal fin is yellow. The swordtail is a third again as long as the body and points in a downward direction. The sword is edged in black with a bright yellow center. If your males body length is two inches , his sword will be three inches or more. Females are colored the same and a re larger but with out the swordtail. There is a population of this fish that has a deep bronze to almost a red coloration.
When X. Montezuma was first collected in 1899 by J.O. Snyder near the town of Rascon in the state of San Luis Potosi in Mexico, adults males where said to be very scarce. However it was probably due to the males are much harder to catch than the females rather than any lack of males in the population. This is also true in the aquarium, the females are much easier to catch than the males. I have never seen a fish avoid the net so easily than this fish. For those of you who don’t know , this is a livebearer. Females will not have a gravid spot like the three previously mentioned and she will also not appear very heavy. However, you will sooner or later see fry swimming in the tank. Females will brood for about 28 days before delivering.
A mature female will produce between 18 and 30 fry. I keep two pairs in a ten gallon tank with a sponge filter and about one third of the tank is loaded with Najas grass. The adults seem to leave the fry alone, but this may depend on the fullness of the adults stomachs.
I feed both the fry and the adults decapsulated shrimp and flake food. The fry seem to grow fairly quickly with the females starting to produce fry of the own after 6 months. I have not tried these outdoors yet, but plan to put some in a smaller pond next spring.