The threadfish is a very popular and well-known aquarium fish. But where does it come from, why is it called a threadfish, what do you need to know about keeping it and what does it eat? We’ll address all this and much more today.
Where does the threadfish live in the wild?
Most threadfish originate from Southeast Asia and South Asia. There they live in very demanding habitats, such as the widespread rice fields found there. It is only thanks to its additional respiratory organ that the threadfish is able to live and survive at all in the warm and therefore oxygen-poor waters. It enables it to breathe air from the atmosphere, which means that it is not dependent on the oxygen dissolved in the water. This respiratory organ is called a labyrinth, which is why threadfish are classified as labyrinth fish.
Why does the threadfish have "threads"?
The special feature of the threadfish is its "threads", which are located on the abdomen. What few people know is that these threads are re-shaped pelvic fins and they fulfil a very specific purpose. Without them, the threadfish would be as good as lost in their habitats. They are there to feel the environment, partners and their food. After all, natural waters are very murky and without the threads the threadfish would not be able to orientate itself, let alone find its food. But what happens if one of these threads is missing? Don't worry, in principle it can continue to live without its threads. Moreover, the threads will grow back as long as the thread attachment is still present and functional. BUT BEWARE: If your threadfish is missing both threads and they do not grow back, it is possible it has a bacterial infection.
Which threadfish species are there?
Threadfish are differentiated on the basis of characterisation, shape and geographical origin. This results in two genera, namely the genus Trichogaster and the genus Trichopodus. The genus Trichogaster includes the threadfish species from South Asia, such as the honey gourami (Trichogaster chuna), striped gourami (Trichogaster bejeus), thick-lipped gourami (Trichogaster labiosa) and the dwarf gourami (Trichogaster lalius).
The genus Trichopodus includes the threadfish from Southeast Asia. These are larger compared to their relatives in South Asia. These include the pearl gourami (Trichopodus leeri), the moonlight gourami (Trichopodus microlepis), the snakeskin gourami (Trichopodus pectoralis), the three spot gourami (Trichopodus trichopterus) and the Trichopodus poptae.
How can I determine if a threadfish is male or a female?
How to determine the sex varies from species to species. It’s sometimes easy and sometimes difficult to do. In the case of the pearl gourami, dwarf gourami and honey gourami, the male is clearly more colourful than his better half and they are therefore easy to distinguish from each other. In other species, however, the colours of males and females are the same. Here you have to examine the dorsal fin of the male. For example, the dorsal fin of the marble gourami, blue gourami, moonlight gourami and striped gourami males is more pointed.
For breeding, the threadfish, like many other labyrinth fish, builds foam nests. These are located on the water surface and are attached to floating plants. The nest is used to store the eggs and the freshly hatched larvae.
What’s important when caring for threadfish?
When keeping threadfish there are differing requirements, depending on the species. It may be that one species can be kept in an aquarium with a volume of 54 litres and another species in an aquarium with a volume of 200 - 300 litres.
Here is an outline for keeping popular threadfish species*:
| Name | Fish size [cm] | Aquarium volume [litres] | Edge length [cm] | pH value | GH value [°dH] | Water temperature [°C] |
|---|---|---|---|---|---|---|
| Blue gourami (Trichopodus trichopterus) | 10 - 11 | from 200 - 300 | from100 | 6 – 8.5 | 2 - 30 | 24 - 30 |
| Thick-lipped gourami # (Trichogaster labiosa) | up to 9 | from 200 | from 100 | 6 – 7.5 | 2 - 20 | 24 - 30 |
| Honey gurami (Trichogaster chuna) | up to 5 | from 54 | from 60 | 6 – 7.5 | up to 15 | 24 - 30 |
| Moonlight gourami (Trichogaster microlepis) | 13 – 15 | from 200 | from 100 | 6 – 7.5 | 25 | 26 - 28 |
| Pearl gourami (Trichogaster leeri) | approx. 12 | from 200 | from 120 | 6 – 8 | 0 – 6 | 24 - 30 |
| Snakeskin gourami (Trichogaster pectoralis) | up to 15 | from 200 - 300 | from 100 | 6 – 7.5 | 5 - 15 | 22 - 28 |
| Dwarf gourami (Trichogaster lalius) | 5 – 6 | from 100 | from 80 | 6 – 7.5 | 15 | 24 - 28 |
*This outline corresponds to the recommendations of the BMEL and the DRTA archive. If you would like more detailed information for keepers of the individual species, you can find out more by following these links:
Basically, threadfish should be kept either as a pair or in a small group. Depending on the species, the size of the group may vary, but a group of 4 fish is usually recommended. An excess of males should be avoided at all costs, for example in the case of the pearl gourami. With regard to socialisation, there are also subtle differences between the individual species. The honey gourami, for example, is a very peaceful fish and is ideally suited to a community aquarium, whereas with the pearl gourami you need to remember to socialise them with less active fish species.
The aquarium itself needs to be densely planted, regardless of the species, and ideally have floating plants so that the threadfish can build their foam nests there (not all species). In addition, the water surface should be calm and without strong currents.
The right food for threadfish – JBL PRONOVO GOURAMI GRANO S
When it comes to food, the threadfish is not choosy. This does not mean that every food is right for it. Its mouth already gives an indication of its feeding habits. It uses its superior mouth to look for food that has fallen to the water surface, such as insects. But larvae and plankton floating around in the water or small crustaceans living on the bottom also end up on the menu.
This varied diet is not covered by every food and therefore does not provide a species-appropriate diet. The JBL PRONOVO GURAMI GRANO S , on the other hand, has been precisely adapted to the needs of threadfish ( and other labyrinth fish). The JBL PRONOVO GURAMI GRANO S takes into account the varied diet from the natural habitats and thus provides a species-appropriate and natural diet. It covers the entire food spectrum of threadfish and, with a 12 % shrimp content, the food also ensures strong colour development in the fish.
With threadfish too, variety is half the battle. Care is thus needed to feed them a varied diet. It is advisable to use a staple food such as the JBL PRONOVO GURAMI GRANO S and then supplement it with other foods.
All JBL PRONOVO foods are made from selected, natural raw ingredients and contain no artificial additives such as colourings. In addition, each food is prebiotic, which means that special dietary fibres provide nourishment for the beneficial intestinal bacteria, thus promoting healthy digestion.
You can find out more about the diet of threadfish in this video:
