Macropodus is a genus of small to medium-sized labyrinth fish native to freshwater habitats in eastern Asia. Most species originate in southern China (including Hong Kong and Taiwan) and Vietnam, but M. opercularis occurs as far north as the Yangtze basin, and M. ocellatus occurs north to the Amur River, as well as in Japan and Korea.

The commonly recognized species in this genus are:

• Macropodus erythropterus Freyhof & Herder, 2002 (Red-backed paradisefish) - endemic to central Vietnam, where only known from the Quang Tri River, a part of the Giang River basin.

• Macropodus hongkongensis Freyhof & Herder, 2002 - endemic to southern China. It is found in mountainous regions as well as lowland habitats. This species grows to a length of more than 10 cm.
  

• Macropodus ocellatus Cantor, 1842 (Round-tailed paradisefish) - Korea

• Macropodus opercularis (Linnaeus, 1758) (Paradise fish) - southern China (including Hong Kong and Taiwan) as far north as the Yangtze basin.

• Macropodus spechti Schreitmüller, 1936 (Black paradisefish)

They are bubble nesters. After the male / female courtship, the male will find a floating structure and build a nest by spitting his saliva mixed with oxygen into a group of bubbles. When the female is ready, the two will wrap under the nest and the falling eggs will be inseminated. The male will gather the eggs in his mouth as they drop and spit them into the bubbles. After mating, he will tend the nest to massage the eggs and weed out any unfertilized or molded eggs. Sometimes the pair will cooperate to tend the nest.

In addition to gills, labyrinth fish or Anabatoidei possess a labyrinth organ in their forehead that allows them to breathe atmospheric oxygen. This is an intricate network of capillaries that acts as an auxiliary breathing apparatus that is able to capture atmospheric air in addition to absorbing oxygen from their gill system. Oxygen is absorbed from a bubble of air taken into the mouth, retained for a although, and then expelled via the gills. A fresh bubble is taken in simultaneously with the expulsion of the old one. Anabantids don’t breathe continually in this manner. Conditions of environment, oxygen content of water, and so on, all affect the use of the secondary organ. It is very important that these fish have access to the surface. If they become trapped or caught under water for a long period of time, they will suffocate. I have lost fish when they become entangled in pump mesh or a sock to hold botanicals. Make sure when you put cloth or mesh in the tank that the fish cannot accidentally get snared in the material. Also make sure any openings or crevices have an escape route so they can swim free. I have lost climbing perches because their spines got snared in a nylon stocking I was using to hold peat moss in the tank. I have lost bettas because they swam into the exit port of an air pipe. Amateur mistakes you can avoid.

Most of the anabantids have a short digestive tract and prefer high protein live foods that digest and pass through their systems quickly and are easily blocked when fed fiber. These fish are insectivores that prey on insects and similar larvae including daphnia, artemia, white worm, grindal worm, etc. Paradise fish will hunt small fish and sometimes eat fry. They will take high protein dry food. If feeding dry foods, the food should have a high percentage of protein above 50% with little or no vegetable fillers. Make sure you provide food with low fiber and fillers. Their short digestive tract does not handle fiber well. They will bloat and this will lead to other ailments quickly.

Characteristics of Paradise Fish

1. Species and Color Morphs

1. In biological terms, the most common definition of a species is that a species is a group of organisms that can successfully breed to produce fertile offspring. Species are also reproductively isolated from other groups, meaning that organisms in one species can't reproduce with organisms in another species. While there are many listed species of macropodus, most are noted as unreliable meaning they are simply a color morph of an existing species. The ‘species’ I have blended are:

• Fork Tailed paradise fish (Macropodus opercularis): This species populates much of east Asia. They have a shorter body and heavier mid-section compared to spechti species. They have a distinct lyre caudal fin . They are usually patterned with a sky blue – cherry red vertical stripe pattern. The top line is usually slightly rounded in the forehead from the lips to the dorsal fin. Males have a slightly longer \ thinner body with long trailing tips on the tail fin. They also have longer trailing dorsal and anal fin tips. Females are plumper with shorter tail fins. The trailing edges of the dorsal and anal fins are cut around 45 degrees.

• Round-tailed paradise fish (Macropodus ocellatus): This species populates nothern east Asia, particularly Korea and China. They have a shorter body and heavier mid-section compared to spechti species. They have a distinct round or spade caudal fin . They are usually patterned dark stripes over brown body with blue spotting on reddish fins under a dark or black veil. The top line is often sharper to the forehead lips to the dorsal fin so the head is slightly triangular,. Males have a slightly longer \ thinner body with sometimes a spade tip on the tail fin. Females are plumper with shorter, rounder tail fins. The trailing edges of the dorsal and anal fins are cut around 45 degrees.

• Black Paradise fish ((Macropodus spechti): This species populates Asia, particularly Vietnam. They have a longer body and thinner mid-section compared to opercularis species. They have a distinct round or spade dorsal fin. They are usually patterned dark stripes over brown body with blue spotting on reddish fins under a dark or black veil. The top line is often rounder to the forehead lips to the dorsal fin so the head is slightly dolphin shaped. Males have a slightly longer \ thinner body with sometimes flowing fiber veins on the tail fin. Females are plumper with shorter, rounder tail fins. The trailing edges of the dorsal and anal fins are cut around 45 degrees.

2. I have also found that mating two separate species may produce off-spring that can reproduce if done correctly. F1 males may not be fertile. But F1 females when bred back to the mother’s specie will produce off-spring that are fertile yet carry traits of the paternal species.