There are few surprises as welcome to an aquarist as a spawning event in their tank—better yet when the fry can be successfully reared. In most circumstances, collecting and growing out the young is a rather daunting task for the average home aquarist with the average means. Special feeds and, sometimes, specialized holding systems are necessary to carry the brood very far beyond the larval or early juvenile stages of development. However, members of the family Anabantidae (the labyrinth fishes) are a very notable exception here.
The anabantids are a distinctive group of mainly Asian tropical freshwater fishes that are famed for their ability to breathe air. Their breathing organ, the labyrinth, is located in a moist pocket under the operculum. This unusual structure confers the ability to withstand oxygen-poor conditions in shallow, overheated pools of water during the dry season. Some species, if kept wet, may even be capable of surviving out of water for hours at a time.
It is likely due to their adaptation to low-oxygen environments (as well as their general hardiness) that they were among the very first species to be imported for the ornamental fish trade. Moreover, they were among the first to be commercially cultured for the trade, no doubt because of the ease with which they could be bred and raised under typical aquarium conditions.
The pearl gourami (Trichogaster leerii) was and still is one of the most popular of anabantids among aquarists. This native of Malaysia is not at all finicky about water conditions, preferring a pH of 6.5-8.0 and a temperature of 75-82°F. It surely does sport a pearly sheen over its body that may be accented with a flash of reddish orange across its belly. Though generally regarded as community species, it can reach a length of over four inches and can (especially mature, courting males) develop a rather pugnacious attitude.
Pearl gouramis are particularly easy to breed and are therefore highly recommended by some as an excellent species for beginner fish breeders to try their hand at. Many pearl gourami breeders prefer to keep a breeding pair by themselves in their own tank (a 10- or 20-gallon aquarium will suffice). Sexing this species is fairly simple. Mature males can be distinguished by their longer, pointy dorsal fin and intensified coloration; fertile females will have a plump appearance and will have a shorter, more rounded dorsal fin. To encourage spawning and promote the development of healthy eggs and fry, the couple should be conditioned prior to breeding. Certainly an overall healthy and naturalistic living environment can help. It will likewise help to build them up with a nutritious, meaty diet (preferably frozen or live) beforehand. Additionally, the temperature should be brought up to somewhere around 80°F.
Like many in the family (e.g. bettas), courtship is preceded rather conspicuously by the construction of a floating raft of bubbles that serves as a nest. Males prefer to build the nest where there is cover from surface plants and where surface water flow is minimal. The nest is constructed bubble by bubble from a specialized saliva-like substance spit out by the fish. As the nest grows, the male will become protective of the area and will turn his attention increasingly to the female(s). Upon completion, he will chase the female under the nest and wrap himself around her, seemingly to squeeze out the eggs. After spawning, it is best to immediately remove the female, as he might attack her relentlessly in his attempt to protect the eggs. Indeed, if left there, she could eat eggs or fry. The male should also be removed as the first fry begin to appear.
The fry hatch out with a substantial yolk sac and do not need to be fed for several days (as long as a week). When ready, they can be offered most types of tiny live feeds (e.g. microworms) or a quality prepared baby fish food. Sometimes pearl gouramis (especially younger females) lay relatively few eggs; still, because of the high degree of parental care and their well-developed state at hatching time, a large proportion of the brood may survive beyond the juvenile stage. As the young approach their second week post-hatch, they can be offered newly hatched brine shrimp (preferably live). The young can be grown out at fairly high densities, albeit with sensible, regular water changes. Use of an air-powered sponge filter can help to maintain adequate water quality. After a few months of growing out on a nutritious diet, the young will begin to look like miniature adults.
If a pair spawns unexpectedly in the community tank, there is still a chance of recovering and transporting the eggs. One exceedingly uncomplicated method is to use a small vessel (such as a Mason jar) to scoop them up with the nest. Simply submerge the jar just under the water level next to the nest, filling it to within an inch or so from the rim. Deliver a very small amount of air to the jar via an air pump. Any dead eggs or fry should be pipetted out of the jar as they are discovered. When the young are ready to feed, they may be moved to a grow-out tank. However, if the aquarist wishes only to keep a small number of young, they can (so long as the water is changed frequently) be maintained as such in the jar for a surprisingly long amount of time.
At around a couple of inches, the young can be either moved back to the display tank (or perhaps brought to the local fish store for trade). Eventually, after a number of successful spawning events, both the aquarist and the fishes will get better at doing their part. So, though you may only be able to raise just a few individuals the first time through—particularly if caught off guard—you just might in time find yourself with more fish than you know what to do with!