Asian Panchax - by Glenn Briggs

Panchax is the common aquarium name for a group of killifish which are adapted to living at the water surface. (The term killifish is derived from kil (old Dutch) which means a small water body such as a ditch or small stream, therefore killifish =  fish from a small water body.)

Panchax are native to tropical regions of West Africa and Asia, including some of the lesser known islands of the Indian Ocean. The origin of this word Panchax relates to a Southeast Asian name for these fish which is Pangchax. The Blue Panchax is referenced to this local native name in its scientific description: Aplocheilus panchax. In the early years of their introduction to the aquarium hobby (circa 1900), most Panchax were considered to be in the genus Panchax and like many other popular aquarium fish, their generic name also became their common name. Other examples of this type of common name adoption include popular aquarium fish such as Rasbora, Platies (originally genus Platypoecilus) and Mollies (a shortening of their former genus name Mollienesia).

Panchax are basically a micro predator, cruising about close to the water surface or waiting beneath floating vegetation to strike at fallen insects or other food morsels. But they will also investigate the depths of the aquarium when searching for food. Primarily surface dwellers, they are good jumpers so their aquarium should have a tight fitting lid. This is particularly important in the first 48 hours after being released into a new aquarium (fish prone to jumping tend to be most active in looking for ways to escape their new home in the first 24-48 hours!)

Inhabiting tropical climates, these fish need to be kept at suitably “tropical” temperatures, eg 22 - 27 C will be fine. From a community tank perspective, most Panchax  are a good addition, adding interest and activity at the water surface. They do very well in planted aquariums, especially if there is some plants at the water surface, which provides a good refuge and makes them feel more at ease.

Panchax will readily accept floating foods such as flake, small granular foods, frozen and live foods. Their temperament can be considered quite good for a community aquarium, as they largely ignore all other co-inhabitants. However, even though most Panchax are moderately sized, they are still a predator, albeit a small one, so it’s probably best not to expect fish such as livebearer fry to survive in the same aquarium. The only Panchax species which definitely needs some extra consideration regarding tankmates is the Gold Panchax. This species is commonly sold in aquarium stores at around 4-5cm, but can grow to 9-10cm - big enough to eat small fish such as a male Endler Guppy or a small Neon Tetra. Tankmates should probably be at least 4-5cm if you are keeping the Gold Panchax.

Panchax are divided into two groups: West African and Asian. The African species tend to be rarely available compared to their Asian counterparts. This is partly because West Africa is a region difficult and expensive to import fish from, and also because most African Panchax are not popular enough to warrant production by commercial fish farms. So they fall into that large category of fishes that is only sporadically available, if at all. But when any West African Panchax do become available, such imports can generate a lot of excitement for killifish enthusiasts and other hobbyists interested in hard to get species.

The West African Panchax are primarily in the genus Epiplatys, containing 20+ species as well as many geographical colour variations. African species most likely to be available are the Red-chinned Panchax (Epiplatys dageti), and its close relative E. chaperi. Species I can recall being imported once or twice in 2-3 decades include E. bifasciatus, E. hildegardae and most recently E. chevalieri (2023). A tiny species E. duboisi was imported a single time, but being very small and quite delicate, nearly all the E. duboisi perished from travel stress. John Cousins here in Melbourne received the few survivors and subsequently bred this tiny panchax which originates from the Congo. Other species such as E. olbrechtsi have also been in the hobby in Australia in past decades, but were usually only kept by a small number of enthusiasts.

With Asian Panchax being native to a region much closer to Australia, we might expect to find the Asian species more commonly available than African Panchax, and that is certainly true to a degree. The Asian Panchax we might see in a Melbourne aquarium shop all belong to the genus Aplocheilus, representing 9 species. The Blue Panchax and the Gold Panchax are the two best known species and are the most commonly imported Asian Panchax. The Gold Panchax is quite popular in the aquarium hobby around the world and is regularly imported into Australia in good quantity.

The fish known as Blue Panchax is a very widespread species, native to India and S.E. Asia, including Thailand, Malaysia and Indonesia. All Blue Panchax were considered a single species (Aplocheilus panchax) but a recent systematic revision split the Blue Panchax into three species. Indian fish are still considered A. panchax, whereas specimens from the Andaman archipelago are now described as A. andamanensis. The Blue Panchax regularly imported into Australia originate from countries such as Indonesia, Malaysia, Singapore and Thailand, these fish are now known as A. armatus. The A. armatus also occurs on Bali which makes it the closest naturally occurring killifish to Australia.

Blue Panchax supplied to the aquarium trade are usually wild caught fish, as they are very common in many regions of SE Asia. When comparing Blue Panchax from different importations, you might detect some colour variations on the body or especially fin colour differences. Sometimes these variations are very subtle, other times they are more obvious.

As an aquarium fish Blue Panchax are quite hardy and undemanding, tolerating a wide range of water conditions. Only growing to 6-7cm, they can be kept with a wide range of community species. Blue Panchax are also extremely adaptable to different water conditions. In nature they occur in pure freshwater habitats, in brackish waters and even in coastal marine habitats such as mangrove swamps! Being a surface dweller, they are fairly easy to spot in the wild, such as in the accompanying photographs which were taken on Pulau Ubin, a small island adjacent to Singapore.

Recently I came across an old article on Asian panchax by the late killifish guru Jorgen Scheel. In the article, Scheel mentions a report in 1958 on Blue Panchax habitat in the Bihar region of India. This region apparently gets cold and frosty in winter and stifling hot in summer. The fish would survive winter water temperatures of 4.5 C and summer temperatures reaching 38 C!! Obviously in other areas such as in Indonesia, the Blue Panchax has much more stable water temperatures year-round.

As mentioned previously, the Gold Panchax (A. lineatus) is a really popular aquarium fish, despite growing to about 10cm which is much larger than other Panchax. The wild form (common name Striped Panchax) is rarely seen these days, having been almost completely supplanted in aquaria by the golden form. This is a shame as the wild form is a nice fish in its own right, with iridescent scales of different colours, dark markings and reddish fins. The gold form (also known as the Golden Wonder) is an aquarium developed strain and is a bright metallic gold. Males of both forms are the more colourful of the sexes. A. lineatus is native to India and Sri Lanka, and has also become established at several locations in Singapore and Hong Kong.

Several other Asian Panchax that are rarely seen these days are the Sri Lankan species Aplocheilus dayi (Ceylon, Green or Day’s Panchax) and A. werneri (Werner’s Panchax).

These two species are very similar in appearance and can be quite difficult to tell apart, especially if you are relying on internet photos as the two are often misidentified by online “experts”.

Both types are very attractive:

A. dayi: males are predominantly bright green, commonly with some tiny black body markings. Females are less colourful but are still quite attractive, as they are boldly patterned with a series of prominent black blotches extending from above the anal fin to the tail.

A. werneri: males are very similar to A.dayi, but have much more prominent black body markings. Females have a black horizontal bar above the anal fin instead of black blotches.       A. werneri has a smaller distribution and has always been less common in the hobby compared to A. dayi.

Reputedly growing to 9cm, these two species are typically exported at around 3.5-6cm. Care is just as easy as for keeping the Blue Panchax. These are great aquarium fishes and used to be regularly imported – all wild collected fish from Sri Lanka. However in recent years they have been quite hard to obtain. This is because an export ban was introduced on all native Sri Lankan aquarium fish species, because the Sri Lankan government was concerned about overfishing of some highly vulnerable species such as the Flame Rasbora (Rasboroides vaterifloris).

Nowadays, the export ban is still in place for the vulnerable species such as Flame Rasbora and Danio Pathirana ( a giant danio type with a highly restricted distribution). Some species considered common such as the various Sri Lankan panchax are once again being exported. (An interesting side note: several endemic Sri Lankan barbs are amongst the most popular of freshwater aquarium fish and are bred in huge numbers around the world: the Black Ruby Barb and the Cherry Barb.)

Dwarf Asian Panchax: Aplocheilus blockii, A. kirchmayeri, A. parvus

These last three species are much smaller than other Asian Panchax, only growing to 4-5cm. This makes them good candidates for nano tanks, or for community tanks of small fish. All are relatively similar in appearance which initially can make identifying individual species difficult. These dwarf species are nicely patterned with spangles over their body and delicately patterned fins. The males develop larger more pointed fins and are more colourful. You could easily overlook them in a bare dealer’s tank as they can be quite shy and plain looking until settled in. A planted tank either as a single species tank or with other small species suits them best. Like many of the other Asian Panchax, these dwarfs are quite happy in pure freshwater or slightly brackish water such as 3-5ppt salt.

A recent import of A. blockii occurred in early 2024, perhaps the first import in a decade or more. This species is known as the Jewel Panchax or Green Panchax.

Then some months later, A. parvus (Dwarf Panchax) was also imported, another first import in many years! I was lucky enough to get 5 of these small fish, which were only about 2cm when imported. At first I placed them on their own in a small breeding tank and would have to sneak up to view them as they were painfully shy. Now around 3-4cm, they are housed in a planted aquarium with tetras and the A. parvus have transformed into very attractive fish. The males glitter with green spangles across their body and fins, and put on elaborate displays to each other when they happen to cross paths.

The third dwarf species A. kirchmayeri has probably not been imported into Australia, it is native to the Goa region of India.

Aquarium care for all the Asian Panchax is fairly straight forward. They will eat most foods, floating or slow sinking foods are useful for these surface feeders. Flake food, frozen Brine Shrimp, granular food and live foods are all eagerly accepted. I have kept them with a range of fishes such as tetras, rainbowfish, small gouramies, catfish and Black Ruby Barbs. The dwarf species should be kept either in a single species aquarium, or with other small gentle species.

Breeding is easily accomplished and is best done in a separate breeding tank, although Panchax will also spawn in a community tank. Spawning mops can be used, like when breeding rainbowfish. The eggs are usually laid near the surface, but I recently found that the Jewel Panchax also laid their eggs near the substrate in a small breeding tank (which is only 25cm high). I also observed Dwarf Panchax males trying to spawn near the substrate in a 45cm deep aquarium.

Generally, Aplocheilus eggs hatch in 12-15 days, the fry will initially eat infusoria, vinegar eels and powder food, before graduating to larger foods such as newly hatched brine shrimp. As the fry grow, they might require occasional sorting to stop predation, separating any “shooters” before they start preying on much smaller siblings. Also, the fry of these Asian Panchax often seem to hide near the bottom, and do not swim at the surface like newly hatched ricefish or rainbowfish.

So if you’d like to try keeping an interesting surface dweller, give some Asian Panchax a go!