Generally Scalar, but really…

I will now try to talk about one of the most fascinating fish in the freshwater aquarium world. The scalar belongs to the order Perciformes, Suborder Percoidei to the family Ciclidae.

The classification of the scalars is still very uncertain due to the scarce presence in the scientific collections of a congruous number of wild specimens and the consequent erroneous habit of using them for the classification also fish bred in aquariums or in any way in captivity.

Generally Scalar

In any case, three species of this cichlid are currently known:

Pterophyllum scalare, Pterophyllum altum and Pterophyllum dumerili

The first (which is the one that is most easily found on the market) has a disc-shaped body just longer than high, the shape is roughly triangular.

Its colouring has four rather evident vertical stripes, mainly black in colour, and the background is usually silver-grey with more or less dark, brown or greenish shades on the back.
Photo by A. Ferrara.

The dorsal and anal fins are considerably large and in the opposite position, the ventral fins are transformed into two rather long filiform rays (usually white or grey), while the pectoral fins are small and of a more or less intense dark colour, sometimes they can also be transparent.

However, these fins are remarkably powerful, in fact, the swimming movement depends almost exclusively on their action.

The length that the Pteropyllum scalare can reach (fins included) is 15 cm, while the height is 25 cm, in particular in the veil fin varieties (so-called due to the “veil” shape of the anal and ventral fins).

The Pterophyllum altum is compressed on the sides and has a triangular appearance much more markedly than the first with an almost straight frontal line. It reaches a maximum length of 20 cm and a height of even 50 cm including fins.

In any case, in captivity, the fish usually remains smaller. The livery cannot be used for classification purposes, however, the background is usually grey/brown with six dark vertical bands between which the first, third and fifth are usually more evident.

Photo by A. Ferrara.

The body colouration usually extends to the fins as well with the exception of the pectoral fins which are usually transparent or dark-mottled. The peculiarity of this species is, according to Pellegrin (1903), the presence above the eye of a sort of notch (the “saddle” nasal area) according to other scientists while this notch is not peculiar to Pterohyllum altum because in nature they have been found (Rio Negro) specimens of the species Pterophyllum scalare showing this characteristic. However, nothing rules out the possibility of hybrids.

The third species Pterophyllum dumerili is similar to the previous species. The peculiar feature that distinguishes this from the other species consists in the dorsal and anal fins, which seem to extend backwards instead of developing vertically, as happens in the other two species.

The origin:

Pterophyllum species are found only in South America.
The area of ​​origin of the Pterophyllum scalare embraces a vast territory which goes from the fluvial regions of the Ucayali and the Amazon River in Peru up to Belém.

The Pterophyllum Altum is perhaps only widespread in the upper course of the Rio Orinoco and Rio Negro. However, it has also been reported in Peru where it lives with the Discus (the reason why the Discus can also live in the tank with the Pterophyllum altum.

Coexistence with the Discus in the tank is also allowed with the other species of Pterophyllum.).

Pterophyllum guerilla has been reported in the Rio Solimoes (Amazon River in confluence with the Rio Negro) and also in the rivers and streams of Guyana.

In any case, the species reported above tend to hybridize in nature, let alone in the aquarium; therefore it is really difficult to find pure breeds at least in Palermo.

The varieties:

The work of breeders has created many colour varieties in Pterophyllum scalare.
A complete classification of these varieties is almost impossible also because new varieties appear on the market every day. I will limit myself to listing only the most common varieties on the market.

Pterophyllum scalare “wild”:

It is very similar to the aforementioned species of Pterophyllum scalare. It has a discoidal body with black vertical stripes on a brown or greenish-silver-grey background.

Pterophyllum scalare “silver”:

The body colour is silver, and the vertical black stripes are clearly visible because they contrast with the background colour.

Pterophyllum scalare “white” (Ghost):

The body is milky white with little or no colour on the fins (the colours on the fins are considered an imperfection). There are no stripes on the body.
Photo by A. Ferrara.

Pterophyllum scalare “golden” (Gold):

The colour of this fish is roughly the same as gold most prominently on the mouth area. At the beginning of the dorsal fin, the fins are generally transparent with some blue dots.

Stripes are absent. In young specimens the pigmentation is dark in the upper part of the body, however, this colouration should disappear with age.

Pterophyllum scalare “black” (Black):

Entirely black body and fins. Stripes also in this variety are absent.

Pterophyllum scalare “black and white” (Half black):

Front body part white and rear part black: the more striking the contrast, the more positively the specimen is rated.

The background is white or at least light followed by dark or golden dots messy all over the body.

General remarks

As I have already said, the scalar is a fish that has been bred and reproduced by many aquarists, in some respects is good in others it is bad:


The Pterophyllum in all species is a fish that in nature lives in waters with acid pH even in the Altum around 5.5 in the other species we speak however of Ph 6 /6.5. The source water of the Pterophyllum is also very soft about 5/ 5.5 dGH.

With breeding and reproduction in tanks, breeders have managed to adapt these fish even to the waters of our aqueducts, naturally treated with a good bio-conditioner to “exclude” metals from the water.

They also hardened the species, making it much less susceptible to disease. And finally, they have created and continue to create (as I said before) many colour varieties of the Pterophyllum scalare species.


However, the breeding of these fish in the tank has led to the weakening of the strains, this effect was caused by the intensive exploitation of the breeding pairs and by the poor hygienic conditions of the breeding tanks. In fact, there are few people who decide to devote themselves to breeding for the pure pleasure of observing the natural reproduction of living beings, behind everything there is always the god of money.

In the second half of the eighties, the deaths of fish (whether fry or adults) led the experts to talk about ADS: Singapores Diseases Angels or the Singapore fish disease and since the acronym was similar to AIDS we even started talking about AIDS of the fish.

Fortunately for the scalars and for all of us aquarists these were only rumours of those who had not studied the case well. In fact, the ads later discovered that it was due precisely to the weakening of the strains and the poor hygienic conditions of the tanks which caused the predominance of pathogens in the already weakened fish.

Another negative factor which is unfortunately known by breeders is the loss of maternal/paternal instinct of the breeding pair, in fact, these do not dedicate themselves to the care of the fry abandoning them to their fate which unfortunately is sometimes that of ending up in the stomach of another fish.

Other times it may happen that immediately after the eggs hatch, the parents do not recognize the children as their own and eat them. 

All these events are caused by the fact that breeders (driven by the usual god of money) in order to carry on more fry and be able to have a higher income separate the parents from the young who, not receiving parental care, do not develop the sense of motherhood/fatherhood.

Once sexually mature, these will reproduce and will also have children. However, for an obvious consequence (not having received treatment and therefore not knowing how to offer it) they will not provide parental care to their children and so on…

The ideal tub.

The aquarium dedicated to the breeding of Pterophyllum guerilla and scalar must be large, (at least, 100 litres of capacity) this if you want to raise a small group of three or four Pterophyllum to attempt reproduction in fact in these cichlids it is very difficult to identify the sex, only in the mating period can it be precisely determined the only sure difference consists in the everted genital papilla; in the male, it is pointed in the female it is rounded (the use of a magnifying glass is recommended to notice the differences).

Don’t be fooled by some rumours circulating in the aquarium world!!!

a) An aggressive fish is not always a male!!!!

b) It is argued that another distinctive sign is the hump that is created on the forehead, a distinctive feature of males. This is not absolutely true, especially in young specimens but also in adults, there may be cases of females with bumps on the forehead.

So for those who want to breed young Pterophyllum scalars, all that remains is to play on the calculation of probabilities, buy four or five specimens and hope that there are at least one male and one female.

Of course, the more specimens you buy, the more likely there will be to form a couple but in this case, you will have to opt for an aquarium with a larger capacity.

If, on the other hand, we have purchased an already close-knit couple, a 60-litre tank is more than fine (excluding the cases of the veil-fin variety) in which case the tank mates, however, must only be bottom fish and cleaners.

However the bigger the aquarium is, the less maintenance it requires, and there is always less chance it will harm your fish who will have plenty of room to swim. The smaller the aquarium is, the more care it requires and could even harm your fish by keeping them dwarfed.

This phenomenon occurs because the fish that has no space stops growing, this is atrocious suffering for the animal and in the background the dwarf fish is not very nice to see.

Another reason why it is advisable to opt for a large tank is dictated by the character of the Pterophyllum (all three species), which are predominantly peaceful fish (they live in schools when young and in pairs when adults), but territorial or are fish that, growing up, delimit their territory (especially when they mate) and defend it at the risk of their own lives if the tank is very small and there is only one good territory, these cichlids will face each other and fight to the death to grab that territory.

The defence of the territory, the species of Pterophyllum, do it through real fights let’s see now how they take place.

Threat Parry:

The fish face each other with spread fins to give an imposing impression of their size, the colours and livery accentuate, (perhaps from excitement) then they begin to intimidate each other, recoiling or advancing everything accompanied by decisive shakes of the head that occur as a way of nervous tic.

The fight:

Finally one of the two fighters springs forward, grabbing the opponent’s lips with his mouth, so the fish drag themselves back and forth in a sort of “iron mouth” until one of the two gives in and flees, punctually chased by the opponent. In addition to the defence of the territory with combat, the Pterophyllum also establish the hierarchy of the tank.

For the Pterophyllum altum you have to pay close attention to the height of the tank rather than the length as they are fish that grow vertically. The bare minimum is a 50cm high tub if you don’t want the aforementioned phenomena of dwarfism.

As far as the decoration of the tank is concerned, we recommend medium-grained, non-calcareous gravel (to see if it is calcareous or not, apply muriatic acid on a sample of gravel if this “frizzes” then the gravel is calcareous otherwise you can buy it quietly) the colour is not relevant, I prefer white which brings out the colours of the fish but it is only a personal taste, many broad-leaved plants are very useful for spawning (for example Echinodorus bleheri, Echinodorus mayor.) and others resistant plants arranged along the edges of the pool (for example Vallisneria, Sagittaria, Echinodorus tunnels, Egeria/elodea densa) some savannah or peat bog wood, some stones neither sharp nor calcareous.

Another little piece of advice that I allow myself to give is the following: As I have already said, the Pterophyllum is a territorial fish, which is why sooner or later it will end up choosing its space in the tank, try to create these territories yourself by placing stones and densely planted plants (at least one with broad leaves) in the various corners of the tank which will allow the fish to find refuge in case of need.

The Pterophyllum, like all species, loves to have its back covered (to feel more protected) which is why I recommend identifying the various territories in the corners of the tank.

Furthermore, always to better delimit the territories, I recommend making use of bamboo canes fixed either with silicone or planted in the gravel and slate slabs placed vertically to facilitate deposition (so your Pterophyllum will have the possibility to choose the place of the deposition).

With a little luck, it will be right there that your fish will go to spawn and if the territory is well-defined you will make it easier for your breeding pair to defend the offspring from attacks by other fish. In addition to this, however, the tank must enjoy large spaces for swimming.

The technical apparatus must invariably be composed of a thermo-heater, an effective biological mechanical filter suitable for the capacity of the tank, and a well-powered lighting system.

In the literature, I have often found it written never to place the Ptrophyllum tank in very busy places in the house with the possibility of hustle and bustle (such as the children’s room or the entrance) because this would disturb the fish.

This is partly true and I have seen it. In fact, when people come to visit me and I host them in my room, a more or less quiet place (where there is also the tank with my Pterophyllums) the fish hole up in the more protected corners of the tank, losing colour because they are frightened.

However, if you have no other place to put the tank (if not in the children’s room or at the entrance) it is not a sufficient reason to give up the Pterophyllum in fact, as I said before, the breeders have accustomed these fish to chemical values ​​that are completely different from their waters of origin, the reason for which, this cichlid can be defined as a very robust and adaptable fish, the consequence of which is that a little hustle and bustle may annoy it for the first time but later it will surely get used to it.

The water

As I have already said several times, the various species of Pterophyllum live in nature in waters with acid pH and low KH (hardness) let’s see it now in detail:

Pterophyllum scalare and Pterophyllum guerilla:

  • 7=<GH>=10;
  • 2=<KH>=5;
  • 5=<pH>=7;
  • NO2=0mg/l
  • NO3= closest to 0
  • The temperature must not be lower than 26° and is tolerated up to 31°.

Pterophyllum altum:

  • 1=<GH>=5;
  • 2=<KH>=5;
  • 5=<pH>=6.5;
  • NO2=0mg/l
  • NO3= closest to 0
  • The temperature must not be lower than 27° and is tolerated up to 32°.

If you are not lucky enough to have water of these characteristics, and you want to attempt the reproduction of Pterophyllum, these values ​​can be obtained with a system for the diffusion of CO2 which also helps plants grow faster and lowers the pH to levels optimal, or filtering with peat which in addition to lowering the pH and gh also helps the health of the fish, in fact, peat contains humic acids and other organic compounds widely present in nature, our friends will live in an environment with characteristics closer to the water where they come from.

These are the most durable and used solutions in the aquarium trade. Personally, I have always used peat in the filter, the only flaw/value (it depends on the personal tastes of the aquarist) is that peat makes the water amber like in the places where the Pterophyllums come from. Furthermore, other solutions are to cut osmosis water to tap water.

Be wary of all substances that chemically lower or raise the values ​​of the water because any substance introduced into the aquarium will be subject to transformations (more or less depending on the very nature of these substances) or, in any case, will cause modifications.

The continuous addition of CO2 and/or peat will bring the system to a state of equilibrium while the occasional addition of various extracts, citric acid, EDTA, or others will force these substances to fight with all the substances found in the tank as a result and that often the results we set for ourselves can only be achieved for a short time.


In nature, the podophyllum is a hunter fish as demonstrated by its hydrodynamic shape (flat) and its agile jerky movements so as to be considered on the same level as a feline. If specimens from their native waters are purchased, most likely they will only accept live food. It will be difficult and require a lot of patience to get them used to food in flakes, granules, freeze-dried, and frozen.

But if your specimens were born and raised in the tank and duly weaned on brine shrimp nauplii, it won’t be difficult for them to consume the various foods that can be found in all aquarium shops. Orient yourself on the fact that the podophyllum is an omnivore therefore an insect-based product and one based on plants cannot really be missing in the diet of your podophyllum.

In addition to these, I use frozen food a lot as a variation on the flakes by administering it every day.

Chironomus, white mosquito larvae, tubifex, daphnia, brine shrimp, small earthworms, and enchytrea. Recently, however, I discovered that my pterophyllums are very fond of seawater fish eggs. In fact, I happened to find a female mackerel (which I had bought to eat) full of eggs. These have been suitably blanched and frozen by me.

From time to time I administer them in the tank where my beloved guests stay who, as I have already mentioned before, devour them.

The live food that must necessarily be administered from time to time to keep the fish in splendid shape is unfortunately very difficult to find; one would have to go into the countryside armed with a net and a special container to obtain it.

The only live food that I personally use is fish fry which unfortunately (for them) is the only one that is easily found. I guarantee you that the Pterophyllum like them very much. When I put the fry in the tank they don’t live more than 5 seconds.

I know it may sound cruel, but that’s nature!!!!!!

ATTENTION: the administration of the food must be done without excesses because the Pterophyllum is a very greedy fish that consumes everything that we administer to it, excessive doses in the long run certainly give intestinal problems to the fish whose abdomen swells immeasurably until dies.

Elizabeth Canales is fond of marine life since childhood and got an aquarium as a gift from her father on her 6th birthday. Since then she started to take care of Coralia (her goldfish). Her love for fish made receive her B.S. in Marine Biology from the University of Washington and DVM from Delaware State University.

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