Interesting

 This is one of the most impressive wild bears. In courtship, the male swings his lavish sword in quick movements with his fins outstretched, while he flaunts his fully dorsal dorsal fin. Males are usually impatient with each other, but in large enough properly placed aquariums with many females, two males can be busy enough to calm down with each other.

As with all wild species, these fish should be kept in aquariums free of fish of different species belonging to the same genus to prevent hybridization.

Scientific studies have shown that in fact females of some species of bears, whose males do not have swords, show that males with swords have an advantage, this is beautifully seen in the species X. montezumae. The female chooses one of the most suitable males. Wild bears, although lacking the primary colors of many domesticated strains, have a sophisticated mesh and rainbow pattern beauty.

With the addition of an extremely long male sword, this fish is extremely beautiful resident of the aquarium. At first, fish are shy, often hiding in plants and responding to sudden or unexpected movements. However, when they get used to the new environment and their number increases, they will spend more time in the foreground and show themselves to you in all their beauty. Males never damage their swords or other fins despite fighting with each other.

  In this species, males need one or two years just to develop swords, which confuses aquarists who think they have a lot of females. This is due to the fascinating socially related trait of maturation. This trait, discovered by RL Borowsky in the early 1970s, involves males literally hiding in a female disguise to avoid the current alpha male or larger males, thereby endangering their own lives. Alpha male, generally finds it difficult to tolerate other males in the aquarium. The growth rate of other fish slows down until one becomes large enough to challenge the alpha male. Transformation into a male happens quickly.

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Population variations

Rio Verde [Rio Gallinas] near Rascon, San Luis Potosi, known as Rio Frio.

It is usually found in streams with strong currents over a base of sand, gravel or rocks.

Fish from the Rio Gallinas system can develop irregular black spots on their hips that can spread to their dorsal fins. These black spots are not present in other populations.

Males other than the Rio Gallinas population have characteristic dorsal fin patterns.

Males may develop a deep bronze to red coloration.

Tamasopo

Rio Gallinas Tamasopo system

Males have a greenish body and a bluish sheen and may develop irregular black spots that form on the hips into patterns that extend into the dorsal fin. The tail fin has a variable pattern  and has a yellow sword with black edges.

Rascon

El Quince in Rio ojo Frio

Males have a bluish sheen all over their bodies and may develop irregular black spots that form on the hips into patterns that extend into the dorsal fin. On the caudal fin is a yellow sword with black edges.

Ojo Caliente

Arroyo La Cienega Ojo Caliente

Males have a bluish sheen on the body with vertical stripes. The dorsal fin is light blue. Pale yellow tail fins with a light blue sword bordered with black.

Capuchin

Arroyo Cienega Grande Capuchin   

Males have a blue / green glow on the body with a pale yellow tail fin and a pale blue sword bordered with black. The dorsal fin is yellow and has two rows of black spots, a row along the bottom and a more irregular row through the middle, and other random spots. No spots on the hips.

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