Labyrinth fish or Anabantoids are a distinct type of tropical fish. While other fish might be capable of only receiving oxygen through the intake of water though their gills, Labyrinth fish possess another respiratory organ that enables them to breathe atmospheric oxygen. Although most fish can survive without coming up for air, the labyrinth organ is actually a necessity in the case of the Labyrinth fish. In fact, the fish itself was named after this special organ.
The Labyrinth fish thrives in habitats where the oxygen in the water can drop to dangerously low levels. While other species might not survive for even few seconds in such harsh waters, the hardy Labyrinth fish can live for several days in this most brutal environment. In fact, as long as these fish are able to keep their body moist, they can live for days even in polluted waters or dried up ponds.
These fish adapt easily to environmental changes and in certain cases, Labyrinth fish are even known to use their pectoral fins to crawl to new water sources. Some species, like the climbing perch, can also climb trees in search of new habitats.
Origin and Habitat
Labyrinth fish generally prefer warmer climates. Most species are therefore commonly found in the tropical waters of the Asian continent. They thrive in the acidic and low-oxygen waters around the south-western, eastern, and southern portions of Asia. Some species can also be found in the slow-flowing waters of South Africa.
In terms of evolutionary age, the labyrinth fish are relatively recent additions to the Kingdom Chordata. Their novel labyrinth organ is perhaps the most obvious give away of their evolutionary progress. After all, most of the more ancient fishes are incapable of breathing in atmospheric oxygen and rely solely on their gills to survive.
The Labyrinth Organ
When Labyrinth fish are placed in an aquarium, you will often observe them rising to the surface from to time to take in big gulps of air. Each intake of air will travel into their labyrinth organ which will then allow them to properly absorb the oxygen. Similar to the maze-like interiors of an actual labyrinth, this special respiratory organ is also composed of several interconnected cavities and compartments.
Located in the fish’s head and behind its gills, the walls of the labyrinth organ is made up of exceptionally thin membranes as well as bony structures called lamellae. The membranes covering the lamellae are known to be thin enough to actually let the oxygen pass through. Once the oxygen makes it through the membranes, it will then be carried along the bloodstream to be utilized by the different parts of the body.
Despite its importance, it should be noted however that most labyrinth fish are not actually born with a fully formed labyrinth organ. Instead, the special respiratory organ only becomes capable of performing its intended purpose once the fish reaches maturity. The actual size of the labyrinth organ can also vary from one fish to the next. It can grow or shrink depending on the oxygen level in the water where the fish grows acclimated to.
Once the Labyrinth fish is fully mature, it will end up relying on its labyrinth organ more than on its actual gills. This is due to the fact that their gills have a tendency to degenerate and become incapable of delivering enough oxygen into their bloodstream. Truthfully, there is a large possibility that Labyrinth fish will die if they are not given the opportunity to come up to the surface to breathe.
Behaviour and Breeding
Aside from their unique respiratory organ, Labyrinth fish also have rather distinct ways of raising their young. They may opt to build nests in underwater plants, keep their fertilized eggs in their mouths, and more commonly they might also build bubble nests on the water’s surface.
Once the female lays her eggs, it is the male who takes full charge of guarding and caring for all of his young. It is also the male Labyrinth fish that blows bubbles to create nest clusters on the water’s surface. The eggs will stay in these bubble nests until they finally hatch.
When the small fry break out of their eggs, the male Labyrinth fish will continue to act as their sole guardian. He will prevent them from straying and take them into his mouth when they begin to drift too far from the nest. For this reason, many males also prefer to build their nest in waters which have little to no current. Their ideal water type is soft, warm, and slightly acidic.
Although these bubble nests are built with the specific purpose of breeding and spawning, some males might also build nests even if they are not raised with any other females. If you ever catch your lone male fish blowing bubble nests, you can simply take it as a sign of his contentment in his new habitat.
Based on their incredible adaptation and survival skills alone, you can already tell that the Labyrinth fish is one that will be able to survive in almost any environment. This makes it an ideal candidate for a beginner aquarium owner.
A few of the most well-known aquarium fish that fall under the Anabantoid category are the Siamese Fighting fish, the Gourami, and the Paradise fish. As previously stated, these fishes thrive in waters that are slightly acidic and possess very low currents.
When left in the wild, these fish can easily thrive in in harsh, heavily vegetated, and possibly polluted waters. They can live in various water levels which range from free flowing streams and rivers, placid ponds, and even manmade fields and ditches. Their innate hardiness makes these types of fish very easy to please and care for.
When placed in an aquarium, Labyrinth fish prefer well-lit but not overly bright tanks. Aside from the more delicate Parosphromenus genus, most of Labyrinth species can tolerate water temperatures of up to 80 °F. Conversely, the Chocolate Gourami prefers to be kept in harsher and more acidic waters.
In decorating your aquarium, it is recommended that you add a few well-placed rocks and a few pieces of driftwood around the tank to provide your fish with some thoughtful hiding places. In terms of feeding needs, Labyrinth fish are easy to feed and are readily accepting of fish flakes and pills. Likewise, they will greatly appreciate a serving of worms and brine shrimp every once in a while.
In the end, this undemanding fish can serve as a great addition to your tropical fish tank. Labyrinth fish get along best with similarly peace-loving Barbs, Tetras, and bottom-dwelling Gobbies and Catfish. You can also put them together with other Labyrinth fish of similar sizes. However, you should avoid putting them together with aggressive fishes such as cichlids since they have a tendency to get rowdy particularly during the breeding season.