Care
Paradise Fish are known from a huge array of heavily-vegetated lowland habitats, including small slow-flowing streams and irrigation channels, to paddy fields, marshes, and the sluggish backwaters of large rivers. These labyrinth fish are even known to colonise fairly stagnant standing waters with low oxygen content, due to their specialised atmospheric air-breathing ability. The home aquarium should be spacious and furnished with plenty of driftwood and tall plants which will grow to create a good amount of surface cover. Floating plants can also be included to help diffuse bright lighting, and a dark substrate and background will help these fish to feel secure and show their best colours. Try to create a maze-like habitat with plenty of visual barriers to break up lines of sight, as these fish can be rather territorial. Filtration should be efficient, but water movement gentle, to emulate the calm conditions these fish prefer. Although Paradise Fish are very adaptable and live in regions with seasonal fluctuations in temperature, they show their best colours when at their breeding temperatures above 22-24 °C . Constant tropical temperatures will age this fish prematurely.
It is important to leave a small gap of warm air between the water's surface and any coverslides in order for these labyrinth fish to come up and gulp air from time to time. A good cover will also prevent your Paradise Fish from jumping clear of the aquarium should they become startled. A species-only aquarium is the most suitable environment for these fish, due to their somewhat territorial and micro-predatorial nature. However, if tankmates absolutely must be kept, choose them very carefully, as small fish will be eaten, and nippy fish will damage the trailing fins of the Paradise Fish. Avoid keeping with any similar-looking fish, such as dwarf gouramis and Bettas. Whilst juvenile Paradise Fish are often seen swimming happily together in groups in dealer's aquaria, they will soon mature into territorial fish that show pronounced intraspecific aggression, particularly the males as they reach sexual maturity. Females tend to be much less aggressive and a single-male, multiple female group can be maintained together quite successfully in a suitably furnished tank.
Interestingly, the Paradise Fish was one of the first ornamental fish to be introduced to the European fishkeeping hobby back in 1869, or possibly in 1665 when Samuel Pepys wrote of seeing 'finely-marked fishes in a glass bowl' and this species is certainly more ornate than the goldfish which some claim that he was referring to. A number of selectively bred colour forms are available, including albino, xanthic, and line-bred forms with enhanced blue or red colouring. Blue and brown forms may reflect regional variation within the range of this species. Also known as the Chinese Fighting Fish in some parts of south-east Asia.
Feeding
Offer a variety of dried foods, plus regular feedings with frozen fare such as Mysis shrimp, vitamin-enriched brineshrimp, bloodworm, and white mosquito larvae etc. Warning: capable of taking small fish - choose tankmates with care.
Breeding
Paradise Fish are fairly easy to breed in the home aquarium. Like many anabantoids, this is a bubble-nesting species, and the spawning process is very interesting to observe. A separate aquarium should be set-up for the spawning attempt; ideally this will be shallow and have tight fitting covers with no gaps. The tank should be filled mostly with water from the main aquarium (adding a small top up of fresh water), and a gentle air-driven sponge filter installed. Do not fill the aquarium right up - be sure to leave a decent gap at the top for a warm, humid layer of air to form above the water once the covers are shut (you can seal the tank top with cling film if the coverslides don't provide an airtight seal) as this will help the young to develop their labyrinth organ. Add some clumps of plants such as Ceratophyllum and Java Moss, set the temperature to around 26 °C, and then acclimatise a well-conditioned pair across. The male should soon start to build his bubble nest - he does this by swimming to the surface, drawing a little air into his mouth and enveloping it in a film of saliva, forming bubbles that then stick together in a raft formation at the water's surface, usually underneath a bit of surface vegetation. During the nest construction stage, the female is vulnerable to attack from the male if he sees her in the close vicinity, which is why the addition of plants is important not only to anchor the nest to, but to help provide cover for the female. Once the nest is complete, the behaviour of the male will markedly change, as he entices the female underneath his nest, embracing her in the typical anabantoid spawning position, whereby the male wraps himself around the female as sperm and eggs are released simultaneously. As the pair drift apart, the male gathers up any eggs that have not floated upwards to the safety of the nest, by taking them into his mouth and placing them in the nest one by one. He will repeat this until all eggs - which may number as many as 500 - have been safely gathered, and then proceeds to guard the nest until the eggs hatch. At this point, the female must be carefully removed and acclimatised back to the main aquarium for her own safety. The eggs should hatch within 48-96 hours (temperature dependent) and as the miniscule fry emerge, the nest will break apart. The behaviour of the male fish can be a bit unpredictable, but most are usually ok to stay with the fry for the first day or two - just observe carefully at this point. Some aquarists, however, prefer to remove the male as soon as the fry hatch, to prevent him from predating on them. Once free-swimming, the tiny fry require infusoria for the first week or so, moving on to baby brineshrimp (Artemia nauplii) and microworm as they grow. It is not uncommon for the young to develop at vastly different rates, and so it is essential that extra rearing tanks are set up in order that you may separate the smaller and larger fry, to prevent bullying and/or cannibalism.
