Rainbowfish

Most rainbow fish originate from Australia and belong to the family Melanotaeniidae, while blue eyes are found on New Guinea and belong to the family Pseudomugilidae. (some blue eyes can be found in Australia and virse versa) A number of experts argue that rainbow fish and blue eyes should be placed in the same family due to their similarities and bordering geographical distribution.

This article will focus on rainbow fish, but much of the information is true for blue eyes as well as the two groups are very similar and have similar requirements. In addition to obtaining general information it is always a good idea to research the specific species of rainbow fish or blue eye fish you’re interested in before brining it home.

Rainbow fish are today quite popular but it has not always been that way. Up to quite recently rainbow fish were a rare sight in aquariums. It is a bit surprising that they didn’t gain popularity earlier as they are hardy, easy to breed commercially and in the home aquarium, and very colourful. Some species are very small and can be compared to small tetras while other can reach a length of 8 in / 20 cm.

Rainbow fish do great in community aquariums with other peaceful species but should not be kept with aggressive fish. They can be kept with semi aggressive species such as angelfish if the aquarium is big enough and there are areas of dense vegetation for them to duck into. The safest course of action is to keep them with other species of a similar size as they can have a hard time competing with larger fish for food. This is especially true for the smaller species of rainbow fish.

Rainbow fish are schooling fish and should ideally be kept in groups of at least 10 – 5 fish but can be kept in groups of 6 and up. You should never keep less then 6 rainbow fish. The fish will feel more secure and display a more vibrant behaviour and a more colourful exterior when kept in a large enough school. They will also display more colour if there is more than one male in the tank.

Rainbow fish prefer an aquarium that is heavily planted in some areas but still have a lot of open space to swim in. They also like an aquarium that has a lot of moss (like java moss) on the bottom for them to deposit their eggs on. It is important to keep the aquarium well covered as they are excellent jumpers.

Never judge a rainbow fish based on how it looks in the store; look at pictures of adult schooling rainbows of that particular species online instead. Pet store usually offer young rainbow fish and young specimens often have dull, camouflaging colorations. They will become much more beautiful as they mature in your aquarium. It is also common among fish stores to keep rainbow fish in less than optimal conditions which reduces the coloration of the fish even further.

All rainbow fish species have similar demands in regards to desired water chemistry, temperature, breeding habits etcetera. There are however some differences and it is therefore advisable to research the exact species you want to keep.

Different species needs different size aquariums, and the length of the aquarium is the most important factor (depth is less important) when determining if the aquarium is suitable for rainbow fish.

There are a lot of different livebearers but only a few species are common in the aquarium trade. Most of the species that are common in the hobby looks very different from their wild cousins due to having been selectively bred in captivity for so many generations. Two examples of this are the guppy wish is much smaller with smaller fins in the wild and the swordtail which is a green, not red, fish in the wild. Another example is that the black molly was formed through line breeding; wild mollies are not pure black. The wild versions are often very beautiful in their own right and often hardier than their line breed counterparts. If you encounter the natural form of these fish it can be well worth giving them a chance.

Live bearers are often recommended to beginners and many of them do make good beginner fish, but there are other species that are even more suitable as beginner fish. The livebearers where once the ultimate beginner fishes but they have become much more sensitive over the years due to continued development and mass production of fish. I do for instance not recommend the black molly to beginners anymore as it today unfortunately can be a quite sensitive fish.

Many of the most common livebearer species in the trade belong to the family Poeciliidae. In this family, you will for instance find the well-known molly, platy, swordtail, and guppy. Another commonly kept family is the family Hemirhamphidae where you will find the popular halfbeaks.

Most livebearers and virtually all commonly kept livebearers are ovoviviparous, i.e. the young develop from retained eggs inside the body of the female but the eggs are independent from the mother. There is however some viviparous species as well; their young get nutrients directly from the mother through her blood which runs through structures that can be compared to a placenta. The halfbeaks are for instance viviparous while all Poeciliidae specis are ovoviviparous.

It should be noted that some species of fish, e.g. the South American freshwater stingrays, aren’t considered livebearers in the traditional hobbyist sense of the word even though they give birth to live young.

Livebearers are best kept in aquariums with a lot of plants along the sides and back and open space in the middle to swim in. This is generally true for all livebearers although some livebearers prefer more plants than others. Livebearers can be kept with other small non-aggressive fish species.

Most common live bearers are easy to breed and often spawn spontaneously in community aquariums. Some fry might survive in a community aquarium but most will end up as food. If you want to save your fry you can move the female to a breeder cage or to another aquarium. You can also move any fry you see to a breeder cage or another aquarium but this will never be as effective as allowing the female to give birth out of harms way. The female will eat her own young and will show no care for the fry once they have been born, so get her away from them as soon as possible after the birth. The fry grows quickly.

Poecilia latipinna

Labyrinth fish are only found in freshwater in Asia and Africa. Most species are Asian and amd can be found in Eastern, South Eastern and Southern Asia. In Africa a smaller amount of species can be found on the southern half of the continent. Labyrinth fished as re primarily but not exclusively found in warm, slow-flowing, low-oxygen waters

Labyrinth fish comes in a wide variety of shape and sizes. Species common in the trade ranges from small honey gouramis to gigantic giant gouramis. There are even labyrinth fish species that have learned to climb in trees.

There are many hardy species of labyrinth fish that are suitable for beginners and can be kept in community aquariums but there are also a lot of sensitive species that are best left for experts and that need species tanks. Example of such sensitive species is the chocolate and liquorice gouramis. Examples of species suitable for beginners include the blue, white and yellow gouramis, the common Betta, pearl gouramis, snakeskin gouramis and a lot of other species.

The betta fish is so popular that it has its own section here at tropicalfishaholic.com and if you want to know more about Betta fish you should visit the Betta section.

Most common labyrinth fish species are easy to breed or at the very least possible to breed in home aquariums. Most species are carnivores but some species eat vegetables and algae as well. Some species can spit water to knock insect in to water similar to the archer fish. Other species can climb trees in their hunt for insects. Most species are active during the day but there are some nocturnal species as well.

Most labyrinth fish show some kind of care for their fry. Many species are bubble nest builders but there are also many species that are mouth brooders or spawn in a cave.

Several species of labyrinth fish are important food fish in Asia. This is especially true for the Giant Gourami that is farmed in huge quantities. Some smaller species are also important food sources and species we keep in aquariums like the kissing gouramis is a common food fish in some areas.

The Giant gouramis have been introduced to many countries across the world due to their quality as food fish and people tried to introduce it to a lot of other areas as well unsuccessfully. Areas where they tried to introduce the fish but failed include Southern France and California.

The common carp (Cyprinus carpio) was introduced to Japan 400 to 600 years ago but Koi breeding isn’t believed to have commenced until the 1820s. This makes Koi a much younger fish than the goldfish which has been selectively bred for over a millennium.

The first place to farm ornamental Koi carp was the town of Ojiya in the Niigata prefecture on the north-eastern coast of Honshu Island. Koi was more or less unknown in the west before 1914 when Niigata koi were exhibited in the annual exposition in Tokyo. After this, Koi keeping exploded in popularity in Japan and the rest of the world eventually followed. In Japanese, the word Koi simply means carp. The proper Japanese word for this ornamental fish is instead nishikigoi.

Koi come in a long row different types and colorations. Common colours include white, black, red, yellow, blue, and cream. New Koi types are constantly being developed and the Ghost Koi and Butterfly koi was for instance not developed until the 1980s. These are by some not considered true Koi (Nishikigoi).

Koi are hardy fish suitable for garden ponds and they will accept a wide variety if different foods. They are cold water fish and do well in the 15-25 degrees C (59-77 degrees F) range. They should not be kept below 10 degrees C (50 degrees F) as their immune system more or less turns off at that point. This can cause problems for them under long cold winters.

Note that goldfish are not Koi and Koi are not goldfish. They where developed in different countries with almost a 1000 years between them.

Some of the more common types of Koi are:

Asagi (浅葱?) A koi that is light blue above and red below.

Bekko (鼈甲?) A white-, red-, or yellow-skinned koi with small black markings, so called sumi (墨?).

Doitsu-goi (ドイツ鯉?) A German mirror carp with only a single line of large mirror-like scales along the top.

Goshiki (五色?) A black koi with red, white, brown, and blue accents.

Hikari-moyomono (光模樣者?) A koi with coloured markings over a metallic base, or a koi displaying two metallic colours.

Kawarimono (変わり者?) Any Koi that does not fit into any other classification.

Kinginrin (金銀鱗?) A koi with metallic scales.

Kōhaku (紅白?) A white-skinned koi with large red markings on the top. The first type ever to be classified.

Koromo (衣?) Koi with patches of blue- or black-edged scales.

Kumonryū (九紋竜?) Kumonryu is a black fish with curling white markings.

Ochiba (落葉?) A light blue koi with yellow patches.

Ōgon (黄金?) A koi of one color only, but with metallic scales.

Shōwa Sanshoku (or Showa Sanke) (昭和三色?) A black koi with red (hi 赤) and white (shiroji 白地) markings.

Shūsui (秋翠?) A koi that has no scales, except for a single line of large mirror scales dorsally, extending from head to tail.

Taishō Sanshoku (or Taisho Sanke) (大正三色?) Very similar to the Kohaku, except for the addition of small black markings called sumi (墨?).

Tanchō (丹頂?) Any koi with a solitary red patch on its head.

Utsurimono (写り者?) A black koi with white, red, or yellow markings.

Ghost koi A hybrid of Ogon and wild carp with metallic scales.

Butterfly koi A hybrid of koi and Asian carp with long flowing fins. This type was created in the US and introduced to Japan. Many do not recognize this and the Ghost carp above as true Nishikigoi.

Koi Types

Devils hole pupfish

Killifish, or killie fish as it is also sometimes spelt, is a collection of small egg laying fish. The group includes families such as Aplocheilidae, Cyprinodontidae, Fundulidae, Nothobranchiidae, Profundulidae, Rivulidae and Valenciidae. There is a total of approximately 1,300 described species of killifish. Roughly 320 species belong to the family Rivulidae; the biggest of all Killi families.

Most killi species are small 2.5 to 5 cm (1 to 2 in) fish, but there are larger species as well and the biggest killies grow to be 15 cm (6 in).

Killifish are spread throughout a very large part of the world and can be found almost everywhere provided that the climate in warm enough. They are not found in Northern Asia and northern Europe, and in the Americas they aren’t present north of southern Ontario. Australia and Antarctica are also without killies.

Killifish can sometimes have very limited habitats which makes them prone to extinction. An example of such a small distribution is the Devils Hole pupfish (Cyprinodon diabolis) which can only be found in the small Devils hole cave in the U.S. and is near extinction.

When we hear the word killi many of us think about annual fish that live in temporary ponds and flood plains and have a quick lifespan where they spawn before the water evaporates and where the eggs then lay dormant waiting for new rains. This is true for the members of certain killifish genera, such as Austrolebias, Gnatholebias, Nothobranchius, Pterolebias, Simpsonichthys, and Terranatos, but most species of killifish are actually found in permanent streams, rivers, and lakes, and live between two and three years.

Some killifish are schooling but most are territorial fish where the male defends a territory and the females within it. The killifish male usually allows immature males in their territory but not adult ones. Most species can live in groups when kept in aquariums as long as the aquarium is big enough for the species and you keep more than three males in the tank.

Most killifish species are carnivores feeding on mosquito larva, crustaceans and worms. Some species hunt other fish. Other feeding behaviours can also be found within the group, e.g. the filter feeders of the genus Orestias.

The ideal setup for killifish varies between different species and you should if possible research the species or at least the genus before you get a killi. The different species within the same genus often have similar demands and if you are successfully at keeping one species you can consider keeping others as well. Generally speaking, many killi species appreciates a lot of plants and some java moss on the bottom of the tank. Many species also like some floating plants.

Considering how colourful, hardy and easy to breed many killifish are it is surprising that they aren’t more common in the hobby. It can often be hard to find killifish in aquariums stores, and if they do have any they normally have just one or two species. If you want to get a hold of a certain species it is better to contact killifish societies and associations. Joining an association can be a great move if you’re interested in these colourful gems.

Goldfish

Goldfish are very popular aquarium fish and are sold in large quantities world wide. It is a man made fish that has been developed through selective breeding over a very long period. Goldfish has been bred in China for at least 1000 years. The regular goldfish was the first goldfish type but a long row of different types of goldfish have been created since then. The scientific name for the goldfish is Carassius auratus. It was one of the first fishes to be kept domestically. Other early species include moray eels and tilapia fish.
It is not 100% sure from which species the goldfish has been bred; many think it hails from the Prussian Carp (Carassius gibelio) but there are other candidates as well. If goldfish are left to breed on their own in a body of water they will over time devolve back into more brownish fish.

Asian carps, a collective name for many different species including the Prussian Carp, naturally produce offspring displaying red, orange or yellow colours once in a while. These mutations are rare but not exceptionally so. This phenomenon was first recorded (in surviving documents) in the Jin Dynasty (265–420 A.D.). Chinese fish keepers eventually started using these mutations for selective breeding, especially the golden ones. The golden carps were displayed as ornaments and hence began the story of the goldfish.

Goldfish can despite their name have many different colours, not just gold. They can for instance be white, black and/or platinum as well, and several types of goldfish do not show any golden colouration at all, e.g. the Black Oranda.

As mention earlier, there are a lot of different types of goldfish. They can according to tradition be divided into five main types:

Dragon eye goldfish are goldfish with extended eyes, e.g. Black Moor, Bubble Eye, and Telescope eye goldfish.

Egg goldfish are goldfish without a dorsal fin. e.g. Lionhead. Any goldfish that lacks dorsal fin belongs to this group, even if it could also fit into another group.

Wen goldfish are goldfish with dorsal fin and a fancy tail. e.g. Veiltail.

Ce (also known as “grass”) are common goldfish that look quite similar to the wild carps except for the colouration.

Jikin and Wakin goldfish are goldfish with double tails, but with the body shapes of comets.

The Common, Comet, and Shubunkin varieties of goldfish are similar to wild carp but with more striking colorations.
Common types of fancy goldfish include: Black Moor, Bubble eye, Butterfly tail, Calico, Celestial eye, Fantail, Lionchu, Lionhead, Oranda, Panda Moor, Pearlscale, Pompom, Ranchu, Ryukin, Telescope eye, and Veiltail.
More rare types of goldfish include: Tosakin or curly fantail, Jikin or peacock tail, Shukin, Tamasaba or sabao, Meteor goldfish, Egg-fish goldfish, Curled-gill goldfish or reversed-gill goldfish, and Mirror-scale goldfish.

Different types of goldfish can be kept in different setups and grow to different sizes. The fancy goldfish types do for instance prefer warmer waters than the types that are more similar to the original goldfish. All types require oxygen rich water to thrive, so the most important factors to consider when keeping goldfish is to keep the oxygen level high and not to overfeed them. Goldfish have vey small stomachs and should not be fed to muoch, especially not if you feed flake food or pellets since dry food will expand when in water and in the stomach of the goldfish.

Cyprinids are native to North America, Africa, Europe, and Asia. The largest species in the family is Giant Barb (Catlocarpio siamensis) which may grow up to 3 metres (9.8 feet). The smallest species is Danionella translucida which grows no bigger than 12 millimetres (0.47 inches).

Some Cyprinids are very easy to breed while other species are highly challenging. All species are egg layers and most species do not show any parental care towards the fry although there are some exceptions to this rule. One such example is the Bitterling which deposit its eggs in bivalve molluscs.

Cyprinids are more then just popular aquarium fish; this family also includes a lot of important food fish. Cyprinids are farmed throughout Eurasia and have over the centuries been introduced to a lot of waters across the world. One famous such water is the river Elba in Spain; a river with extremely clear water to which the carps were introduced by the Romans. It is now a popular fishing destination for fishermen who want to catch big wells catfish. Cyprinids use to be a very important food source for land locked countries before fish could be frozen and rapidly transported. Outside their native range, Cyprinids can be very destructive invasive species and they are causing a lot of problems in some areas. Carp species has for instance become a serious problem in Australia.

The fact that many Cyprinids are popular aquarium fish has made them economically important due to the revenue from the aquarium trade. Many Cyprinids are captive bred but there are also many species that are still collected from the wild. This can be a real drain on wild populations which has been shown in the Red lined torpedo barb. It is a relatively new fish in the hobby but due to its rapid gain of popularity it has already become endangered in the wild. Another species with a similar fate is the Galaxy rasbora a.k.a. Celestial danio.

The most popular types of Cyprinids in the aquarium trade are danionins, rasborines and true barbs. Most of the popular species are schooling species and you should get at least 6 specimens for your school, although 10-15 will be even better. If schooling cyprinids are kept alone they will never feel secure and never be the wonderful aquarium fish they can be. Many of these popular species are suitable for beginners and can be kept in community aquariums. It is however as always best to read up on the species you want to keep before getting them as some species have their peculiarities. The Tiger barb as an example should not be kept with long finned or slow moving fish as they have a tendency to nip at fins.

Most Cyprinids are omnivores and will accept most foods you give them. Try to give them a varied diet with some live food now and then to ensure optimal health and good colours.

Cyprinids, especially goldfish, are often used as feeder fish to feed predatory fish. This is a poor practice due to the poor nutritional value in goldfish. Try to get your fish to accept other foods; a more varied and nutritious diet reduces the risk of malnutrition.

Rosy Barb

Betta Fish

The name “Betta” has widely come to mean fish of one particular species, the Siamese fighting fish (Betta splendens), but the term is really the name of the entire genus to which this species belong. The Siamese fighting fish is just one of many members of this genus and it is correct to refer to all of them as Betta fish, but since there is a high risk of confusion it is safer to use their respective scientific names instead. All Bettas are fairly similar to Betta splendens but they do vary quite a lot in regards to size, behaviour and breeding habits.

I will now start by saying a few words about the Siamese fighting fish, henceforth simply referred to as the Betta, before I proceed to talk about some of the other members of the genus.

The Betta is one of the most popular aquarium fishes in the trade today. They are popular chiefly due to their beautiful colours and fins, but there are also aquarists that keep them for their feisty temperament and interesting spawning behaviour. This popularity has led to the development of a large variety of different Betta types through selective breeding and more are constantly being created. One of the latest types is the giant Betta which grows much larger then the regular Betta.

Betta fish are often seen sold in small cups. The male Betta fish is very aggressive and will normally kill other Betta males if they are kept in the same aquarium. You will need a very large and cleverly decorated aquarium if you want to keep more than one male. This one of the reasons why so many pet stores house them in vases, tiny glass cubes and similar. This is however not ideal conditions for them; they prefer a larger home.

Females are less aggressive and can be kept together although there is a risk for aggression in females as well. It is best to always keep 3-4 females with one male. This is to reduce the stress each female suffers from the courting male. If you have just one female he might kill her with his romantic advances.

Betta fish can be kept in small aquariums but will do best in an aquarium that is at least 10 gallon / 40 L with a lot of plants and some open area to swim in. They like to have plants near or on the surface as this gives them something to attach their bubble nest to. They are best fed a varied diet including frozen and live food. Avoid strong surface current as this can destroy their nests. The Betta fish breathe atmospheric oxygen and will drown if it is not allowed to surface for air.

Betta fish are easy to breed. The male builds a bubble nest and try to lure a female in under it to spawn with her there. The eggs are kept in the nest until the fry hatch and become free swimming. The male will guard the nest from any threats. The fry is very small and need to be given very small food.

Other Betta species are much less common in the trade but can be found from time to time. Some species show a lot less aggression than Betta splendens and makes it possible to keep several males in the same tank. When it comes to reproduction, not all species build nest – some are mouth brooders. An example on such as species that is quite common in the trade is Betta pugnax aka the Mouth brooding betta. This fish is however despite its name not the only mouth brooding Betta. The care requirements differ between the different species in the genus Betta although most of them want a calm, planted aquarium. I strongly recommend reading up on the specific species you want to keep before getting any Betta.

Common pleco

The term Pleco traditionally meant Hypostomus punctatus, the Common pleco. However, during the last two decades the pleco keeping world has gone through a renaissance and there is now a wide variety of related species available in the trade. The term pleco has therefore changed and turned into a name used for a large number of different catfish species in the family Loricariidae. This family includes carnivorous plecos, omnivore plecos, and algae eating herbivore plecos. Some species also need drift wood as a part of their diet to survive.

Different pleco species varies a lot in price and while some species are cheap and commonly available others are expensive and hard to find in ordinary pet shops (you have to place a special order).

Some aquarists believe that it means bad luck for your tanks if you spell out the word pleco and it is therefore rather common to see it written as Pl*co in forums. I leave it up to you if you want to believe this to be true or not.

The family Loricariidae includes a very large number of species and is destined to grow as more and more species get described by science. The hobby contains a lot of well known but undescribed species and they are assigned an L number to make them easier to identify and discuss. L = Loricariidae and then a number. An example is L146 which is the very popular and beautiful Zebra pleco. The Zebra pleco has now been properly described and given a scientific name (Hypancistrus zebra), but the L number is still commonly used among aquarists. This is true for a lot of other plecos as well; the L number tend to stick even after they have been given scientific names.

The smallest plecos available on the market will reach a length of 1 in / 2.5 cm or slightly more as adults. There are several plecos species that are very common in pet shops despite the fact that they grow to be about 2 ft / 60 cm long. These species are best avoided unless you have a huge aquarium. To prevent unpleasant surprises, it is always strongly recommend that you study the exact species you are going to get in books and online before you buy them.

Considering the fact that plecos range so greatly in size and the fact that they come from very different environments and have very different dietary demands it should come as no surprise that it is next to impossible to give any general care and feeding advice for plecos. However, this great variation also virtually guarantees that you can find a pleco species suitable for your aquarium.

Some plecos are very hardy while others will require perfect water quality to thrive. Many species can be and are breed in aquariums. If possible, ideally buy aquarium or otherwise captive breed plecos since collection from the wild can tax a species rather hard and has led to some species like the Zebra pleco to become endangered. This species can no longer be exported and all specimens in the trade today are captive breed.

The Harlequin shrimp originates from the island Sulawesi in Indonesia where it is collected from a number of freshwater lakes. It lives in freshwater sponges which it cleans by eating debris and algae from the surface of the sponge. This feeding behaviour has earned them their scientific name Caridina spongicola. The Harlequin shrimp does not require sponges to survive and can be fed a wide variety of food in captivity and be kept in a number of different setups.

The harlequin shrimp is a somewhat sensitive shrimp that is hard to keep and it is not recommended for beginners who want to keep their first shrimps. It is normal for this species to loose its colours when introduced to a new aquarium. The colour returns once it starts feeling safe in its new environment, and it is very important to decorate your aquarium in a way that makes the shrimp feel safe with a lot of hiding places. Despite a good setup with a lot of hiding places these shrimps are usually very shy during the first days in a new home.

The best setup for a Harlequin shrimp is one that mimics those Sulawesi lakes from which it originates. The pH-value should preferably be alkaline even though this species can adapt to neutral water or even slightly acidic conditions. The temperature should always be kept above 78 °F / 25.5 °C and an even higher water temperature near 85 °F /29 °C is better. The harlequin shrimp needs good water quality and is very sensitive to nitrogenous waste. If water quality drops it is best not to feed the shrimp for a few days. They will tolerate that better than a prolonged drop in water quality. Harlequin shrimps can be sensitive to rapid changes in the water parameters and large water changes are therefore not recommended. It is better to change a little water often.

Harlequin shrimps are easy to feed and will accept most types of commercial fish food. In the wild they do as earlier mentioned live on sponges where they eat a lot of algae. It is therefore recommended to use an algae based food as the base of their diet. They should however be offered a varied diet that includes occasional meaty treats. They are small shrimps and need to be fed small food. It is best to feed your harlequin shrimps after dark and they should not be fed more then they consume in2-3 hours.

As far as we know it isn’t possible to sex Harlequin shrimps based on external dissimilarities. It is possible that the females are larger but this notion has not been confirmed. The small size of this shrimp makes finding external methods of sexing harder than in other, larger shrimps.

The Harlequin shrimp is hard to breed but will breed in aquariums if kept in ideal conditions. Their reproduction rate is low and they usually only produce 10-15 eggs at a time. The eggs are carried by the female until they hatch after 20-30 days. The baby shrimplets look exactly like their parents with the harlequin pattern. The colour is however less intense in the fry.

Article first published on Petfishdirectory