Despite that paradise fish (Macropodus opercularis) were one of the first fish to be kept by aquarists they aren't as commonly found in home aquariums as other fish species.
This may be because you don't commonly see them for sale in mainstream pet stores. This may also be because paradise fish don't make good fish for community tanks and you certainly cannot keep two male paradise fish together or they will fight.
However, these same characteristics didn't stop bettas from becoming very popular aquarium fish.
In fact, paradise fish are very similar to bettas. Like bettas, paradise fish belong to the family Belontidae and they also possess a labyrinth organ. This organ is located near their gills and allows the fish to breathe atmospheric oxygen.
All labyrinth fish need to obtain oxygen from the water via their gills and oxygen from the atmosphere via the labyrinth organ. If they are unable to obtain oxygen from both sources they won't survive.
Paradise fish are from Asia and in their natural environment often live in muddy, low oxygenated water. As in the betta, the labyrinth organ evolved so that the fish could survive in water with low oxygen.
The temperament of paradise fish is even more aggressive than that of betta splendens. Paradise fish not only fight one another, but they often attack smaller fish species too. It is okay to keep more than one female paradise fish together in your tank.
As you can see in the above photo, female paradise fish (on the left) are not as colorful as the males and their fins are much smaller.
Paradise fish are omnivores, eating both plant and animal based foods. They will readily eat flakes, freeze-dried, frozen, and live foods. They best temperature for them is about 70-75°F (21-24°C). They can survive cooler temperatures but usually won't spawn.
Paradise Fish Spawning
Paradise Fish Fry in Bubblenest
In general, paradise fish are easy to spawn.
For spawning, it is best to place a divider in your aquarium so that the male and female paradise fish can see one another, but can't make contact. Unless the female is filled with eggs and ready to spawn the male may kill her.
Paradise fish are bubblenest builders. The male will build a bubblenest at the top of the aquarium. It is best to have floating plants in the tank. You should have a minimum of water agitation. Some aquarists turn off the filter when attempting to spawn their paradise fish so that the water won't be agitated.
Once the female is ready to spawn (you should be able to tell by her swollen abdomen that is filled with eggs) remove the aquarium divider. Make sure you have plenty of plants in the tank and places for her to hide from the male.
The male will try to get her underneath the bubblenest where they will spawn. The male and female will embrace under the bubblenest releasing eggs and sperm.
The male will retrieve the eggs and blow them into the bubblenest. After spawning is over remove the female, but leave the male in the tank. He will guard the eggs until they hatch about 1-2 days later. The female needs to be removed as soon as spawning is over or the male may kill her - he may see her as a threat to the eggs.
When the fry first hatch they will remain in the bubblenest and absorb the yolk sac. The male will attend to the fry during this time - replacing them into the bubblenest as needed.
Once the fry become free swimming remove the male or he may eat them.
Once they are free swimming feed the fry liquid fry food and infusoria. About a week later, when the fry are older, start giving them newly hatched brine shrimp and powdered food for fry.
If you can't find paradise fish at your local pet store you can often find them online for around $3.50-4.00 each.