Neon iris (Melanotaenia praecox) Weber & de Beaufort, 1922.
This fish has been known in the aquarium hobby since 1922, and 70 years later it came to Europe.
Synonyms
Russian: Melanothenia neon, Melanothenia praecox, Dwarf iris Latin: Rhombatractus praecox Weber & de Beaufort, 1922
Order: Atheriniformes Family: Irises (Melanotaeniidae) Genus: Melanotaenia
Habitat in nature
Melanothenia neon was first described by Weber in 1922, but appeared in the aquarium hobby in the 90s. They live in small rivers and streams in Western New Guinea, and in the Mamberamo region of West Papua. The water in such rivers is clear, with a fast current, a temperature of 24-27C and a pH of about 6.5. Melanothenia feed on plant foods, insects, fry and caviar. Fortunately, these areas still remain some of the least explored on the planet, and the rainbowfish population is not yet in danger.
Options for VPR “VPR 8th grade 3rd option” (mathematics)
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8th grade
mathematics
Option 3
1.
Find the meaning of the expression
2.
Solve the equation
If there are several roots, write them down in the answer without spaces or separators in ascending order.
3.
Goldfish and rainbowfish swim in the aquarium. The number of goldfish is related to the number of irises as 2: 7. How many iris are in this aquarium if there are 14 goldfish in it?
4.
a
,
b
and
c
are marked on the coordinate line .
Mark some number x
so that three conditions are met:
5.
The figure shows a graph of a linear function. Write a formula that defines this linear function.
6.
The graph shows the change in the number of television viewers of a sports football channel broadcasting exclusively Russian football (Russian Premier League, Football National League, national team matches) during 2021. The number of people is measured in thousands.
The chart shows that viewership increased sharply in June and peaked in July. What football event do you think this is connected with? Why is the number of viewers in winter practically equal to 0? Considering the weather conditions in our country, try to explain the reason for this decline. Write two or three sentences briefly expressing and justifying your opinion on these issues.
7.
At school during the holidays they held a “Young Photographer” competition. The competition consisted of two rounds - “Photo Exhibition” and “Graphic Editing”. At the photo exhibition, participants had the opportunity to present their photographic works in five proposed areas. In each direction you could get from 1 to 5 points. If no photo was submitted in any of the areas, 0 points were given. In the second round, participants had to process the unsuccessful photo they were offered in computer programs and graphic editors in order to improve its parameters. The maximum score for the second round was 9 points. The final score is calculated using the formula
Sasha Egorov is one of the competition participants. The tables show the scores he received. Find Sasha Egorov's final score.
| Photo exhibition | |
| Name of direction | Points |
| Landscape photography | 4 |
| Portrait | 5 |
| Reportage | 3 |
| Animal photos | 4 |
| Macro photography | 0 |
| Total (Bvyst) | |
| Graphic editing | |
| Points | |
| Composition (framing) | 3 |
| Color rendition (white balance) | 2 |
| Artistic effects | 2 |
| Total (Bgraph) | |
8.
Mark the numbers and numbers on the coordinate line
9.
Find the value of the expression when
10.
On average, 5 ceramic pots out of 250 have defects after firing. Find the probability that a pot randomly selected after firing has no defect.
11.
Fresh apricots contain 88% water, while dried apricots (dried apricots) contain 30%. How many fresh apricots are required to prepare 72 kg of dried apricots?
12.
ABCD is depicted on checkered paper with a square size of 1 × 1.
.
How many times is side AD
less than the height of the parallelogram drawn to this side?
13.
In a triangle, the angle is 90°, find
14.
Indicate the number of the correct statement.
1) Each side of the triangle is less than the difference of the other two sides.
2) An isosceles triangle has at most two equal angles.
3) If the side and angle of one triangle are respectively equal to the side and angle of another triangle, then such triangles are congruent.
4) In triangle ABC
, for which
AB
= 3,
BC
= 4,
AC
= 5, angle
C
is the smallest.
15.
A square sheet of paper
ABCD
was folded along line
EF
so that point
C
fell on the middle of side
AD
(point
C1
in the figure).
Find the length of the segment DE
if the side length of the sheet is 20 cm. Give your answer in centimeters. Write down the solution and answer.
16.
The Winter Olympic Games are sports competitions held once every 4 years under the leadership of the International Olympic Committee. The Winter Games began in 1924 as a complement to the Summer Games. From 1924 to 1992, the Winter Olympics were held in the same years as the Summer Olympics. Since 1994, the Winter Olympic Games have been held with a 2-year shift relative to the Summer Olympic Games.
The first Winter Olympics took place in 1924 in Chamonix (France), with 293 athletes from 16 countries participating. In 2021, 2,922 athletes from 92 countries have already participated in the XXIII Olympic Games in Pyeongchang (South Korea).
The chart shows three rows of data showing the total number of Winter Olympic medals won between 1994 and 2018 by teams from three countries: Russia, Sweden and France. View the diagram and read a portion of the accompanying article.
France has taken part in every Olympic Games of modern times. Three times she became the hostess of the Winter Olympic Games. The most decorated Frenchman in the history of the Olympic Games is biathlete Martin Fourcade, who won a total of 5 gold medals at the 2010, 2014 and 2021 Games. The 1994 Winter Games were the most successful in the history of France; they brought French athletes 17 medals of various denominations.
Russian athletes have won 141 medals at the Winter Olympics since 1994. The most successful Olympics for Russians was the 2014 Olympics, which took place in Sochi, where Russia won 33 medals.
Sweden has competed in every Winter Olympics, winning a total of 144 medals. In 1994, Swedish athletes won only 3 medals. In 1998, the number of Olympic medals did not change, but at the 2002 Olympics, held in Salt Lake City, 4 more medals were already won. The most successful Winter Olympics for Sweden was the 2014 Olympics in Sochi, where they won 15 medals.
During their performances at the Olympics, Austrian athletes won 232 medals at the Winter Olympics. The Austrians won the most awards in alpine skiing competitions - in this discipline they are leaders. The most unsuccessful for Austria in the last 25 years was the 1994 Olympics in Norway, where Austrian athletes won 9 medals, which is 8 less than at the Olympic Games 1998, 2002 and 2014. The most successful Winter Olympics for the Austrians was the 2006 Olympics in Turin, where they won 23 awards of various denominations. The next Winter Olympics, held in 2010 in Canada, brought the Austrians 7 fewer medals. At the 2021 Olympics, Austria was able to win 14 Olympic medals.
1) Based on what you have read, identify the country whose achievements correspond to the third row of data in the diagram.
2) Using the given description, construct a schematic diagram of the total number of medals won by the Austrian team at the Winter Olympics in 1994–2018.
17.
Segments
AB
and
CD
are
the diameters of a circle with center
O. Find the perimeter of triangle AOD
if it is known that
CB
= 13 cm,
AB
= 16 cm.
18.
Two cars left A for B at the same time. The first one drove at a constant speed all the way. The second one drove the first half of the trip at a speed of 51 km/h, and drove the second half of the trip at a speed 34 km/h higher than the speed of the first one, as a result of which it arrived at B at the same time as the first car. Find the speed of the first car. Give your answer in km/h. Write down the solution and answer.
19.
There are 75 different integers written on the board. Each number was either squared or cubed and the result was written in place of the original number. What is the smallest number of different numbers that could be written on the board?
Solution
1.
Find the meaning of the expression
Solution.
Let's bring it to a common denominator in brackets:
Answer: −2.68.
2.
Solve the equation
If there are several roots, write them down in the answer without spaces or separators in ascending order.
Solution.
Let's solve the quadratic equation:
Answer: 1.52.5.
3.
Goldfish and rainbowfish swim in the aquarium. The number of goldfish is related to the number of irises as 2: 7. How many iris are in this aquarium if there are 14 goldfish in it?
Solution.
Let's calculate the number of irises in the aquarium:
Answer: 49.
4.
a
,
b
and
c
are marked on the coordinate line .
Mark some number x
so that three conditions are met:
Solution.
From the first inequality it follows that from the second, that and from the third, which means x
is in between
5.
The figure shows a graph of a linear function. Write a formula that defines this linear function.
Solution.
From the graph it is clear that the line passes through the points and The equation of the line has the form Solve the system
Thus, the equation of the line has the form
Answer:
6.
The graph shows the change in the number of television viewers of a sports football channel broadcasting exclusively Russian football (Russian Premier League, Football National League, national team matches) during 2021. The number of people is measured in thousands.
The chart shows that viewership increased sharply in June and peaked in July. What football event do you think this is connected with? Why is the number of viewers in winter practically equal to 0? Considering the weather conditions in our country, try to explain the reason for this decline. Write two or three sentences briefly expressing and justifying your opinion on these issues.
Solution.
Football event - World Cup 2021, held in Russia; it lasted from June 14 to July 15, and the national team of our country achieved success during it. That's why the number of viewers increased so sharply during these months.
In winter, the weather conditions are too harsh for both football players and fans. At this time, the clubs go on break, and the TV channel simply has nothing to show due to the conditions of this task.
7.
At school during the holidays they held a “Young Photographer” competition. The competition consisted of two rounds - “Photo Exhibition” and “Graphic Editing”. At the photo exhibition, participants had the opportunity to present their photographic works in five proposed areas. In each direction you could get from 1 to 5 points. If no photo was submitted in any of the areas, 0 points were given. In the second round, participants had to process the unsuccessful photo they were offered in computer programs and graphic editors in order to improve its parameters. The maximum score for the second round was 9 points. The final score is calculated using the formula
Sasha Egorov is one of the competition participants. The tables show the scores he received. Find Sasha Egorov's final score.
| Photo exhibition | |
| Name of direction | Points |
| Landscape photography | 4 |
| Portrait | 5 |
| Reportage | 3 |
| Animal photos | 4 |
| Macro photography | 0 |
| Total (Bvyst) | |
| Graphic editing | |
| Points | |
| Composition (framing) | 3 |
| Color rendition (white balance) | 2 |
| Artistic effects | 2 |
| Total (Bgraph) | |
Solution.
Let's find the final score for each element:
Photo exhibition: 4 + 5 + 3 + 4 + 0 = 16.
Graphic editing: 3 + 2 + 2 = 7.
Thus, the final score will be: 0.62 · 16 + 0.5 · 7 = 13.42.
Answer: 13.42.
8.
Mark the numbers and numbers on the coordinate line
Solution.
Note that the midpoint of the segment is a point with coordinate Since, we find that it is closer to the number −2 than to the number −3. The middle of the segment is a point with a coordinate. Since we find that it is closer to the number 1 than to the number 2. Therefore, the given numbers must be located on the coordinate line as shown in the figure.
9.
Find the value of the expression when
Solution.
Let's simplify the expression:
Let's substitute the value into the resulting expression
Answer: 0.8.
10.
On average, 5 ceramic pots out of 250 have defects after firing. Find the probability that a pot randomly selected after firing has no defect.
Solution.
Let's find the number of working pots: 250 − 5 = 245.
Thus, the probability that the pot will be free of defects is equal to:
Answer: 0.98.
11.
Fresh apricots contain 88% water, while dried apricots (dried apricots) contain 30%. How many fresh apricots are required to prepare 72 kg of dried apricots?
Solution.
Note that the dry part of fresh apricots is 12%, and dried - 70%. This means that to prepare 72 kg of dried apricots, a kg of fresh apricots is required.
Answer: 420 kg.
12.
ABCD is depicted on checkered paper with a square size of 1 × 1.
.
How many times is side AD
less than the height of the parallelogram drawn to this side?
Solution.
From the figure it can be seen that the height drawn from point B
to side
AD
is the segment
BD
- the diagonal of the parallelogram.
Note that segments AD
and
BD
are the hypotenuses of right triangles.
Using the Pythagorean theorem we find AD
and
BD
:
Since BD
is the height of the parallelogram, then side
AD
is less than the height drawn from point
B
to side
AD
by a factor.
Answer: 2.
13.
In a triangle, the angle is 90°, find
Solution.
The trigonometric functions of supplementary angles are similar. That's why
Answer: 0.96.
14.
Indicate the number of the correct statement.
1) Each side of the triangle is less than the difference of the other two sides.
2) An isosceles triangle has at most two equal angles.
3) If the side and angle of one triangle are respectively equal to the side and angle of another triangle, then such triangles are congruent.
4) In triangle ABC
, for which
AB
= 3,
BC
= 4,
AC
= 5, angle
C
is the smallest.
Solution.
Let's check each of the statements:
1) “Each side of a triangle is less than the difference of the other two sides.” - incorrect
, since if we have that
2) “An isosceles triangle has at most two equal angles.” - incorrect
, in an isosceles triangle, the angles at the base are equal, but they can also be equal to the angle opposite the base.
3) “If the side and angle of one triangle are respectively equal to the side and angle of another triangle, then such triangles are congruent.” - incorrect
, equality is determined by three elements.
4) “In triangle ABC
, for which
AB
= 3,
BC
= 4,
AC
= 5, angle
C
is the smallest.”
- true
, in a triangle the larger side lies opposite the larger angle.
Answer: 4.
15.
A square sheet of paper
ABCD
was folded along line
EF
so that point
C
fell on the middle of side
AD
(point
C1
in the figure).
Find the length of the segment DE
if the side length of the sheet is 20 cm. Give your answer in centimeters. Write down the solution and answer.
Solution.
In right triangle C1DE
: By the Pythagorean theorem, and since we find that
where
Answer: 7.5 cm.
16.
The Winter Olympic Games are sports competitions held once every 4 years under the leadership of the International Olympic Committee. The Winter Games began in 1924 as a complement to the Summer Games. From 1924 to 1992, the Winter Olympics were held in the same years as the Summer Olympics. Since 1994, the Winter Olympic Games have been held with a 2-year shift relative to the Summer Olympic Games.
The first Winter Olympics took place in 1924 in Chamonix (France), with 293 athletes from 16 countries participating. In 2021, 2,922 athletes from 92 countries have already participated in the XXIII Olympic Games in Pyeongchang (South Korea).
The chart shows three rows of data showing the total number of Winter Olympic medals won between 1994 and 2018 by teams from three countries: Russia, Sweden and France. View the diagram and read a portion of the accompanying article.
France has taken part in every Olympic Games of modern times. Three times she became the hostess of the Winter Olympic Games. The most decorated Frenchman in the history of the Olympic Games is biathlete Martin Fourcade, who won a total of 5 gold medals at the 2010, 2014 and 2021 Games. The 1994 Winter Games were the most successful in the history of France; they brought French athletes 17 medals of various denominations.
Russian athletes have won 141 medals at the Winter Olympics since 1994. The most successful Olympics for Russians was the 2014 Olympics, which took place in Sochi, where Russia won 33 medals.
Sweden has competed in every Winter Olympics, winning a total of 144 medals. In 1994, Swedish athletes won only 3 medals. In 1998, the number of Olympic medals did not change, but at the 2002 Olympics, held in Salt Lake City, 4 more medals were already won. The most successful Winter Olympics for Sweden was the 2014 Olympics in Sochi, where they won 15 medals.
During their performances at the Olympics, Austrian athletes won 232 medals at the Winter Olympics. The Austrians won the most awards in alpine skiing competitions - in this discipline they are leaders. The most unsuccessful for Austria in the last 25 years was the 1994 Olympics in Norway, where Austrian athletes won 9 medals, which is 8 less than at the Olympic Games 1998, 2002 and 2014. The most successful Winter Olympics for the Austrians was the 2006 Olympics in Turin, where they won 23 awards of various denominations. The next Winter Olympics, held in 2010 in Canada, brought the Austrians 7 fewer medals. At the 2021 Olympics, Austria was able to win 14 Olympic medals.
1) Based on what you have read, identify the country whose achievements correspond to the third row of data in the diagram.
2) Using the given description, construct a schematic diagram of the total number of medals won by the Austrian team at the Winter Olympics in 1994–2018.
Solution.
1) Based on the diagrams, it is clear that the country whose achievements correspond to the third row of data in the diagram is Russia.
2) Let's build a diagram of the total number of medals won by the Austrian team at the Winter Olympics in 1994–2018:
17.
Segments
AB
and
CD
are
the diameters of a circle with center
O. Find the perimeter of triangle AOD
if it is known that
CB
= 13 cm,
AB
= 16 cm.
Solution.
Consider triangle AOD
and triangle
COB
: since
AO
=
OB
=
r
;
CO
=
OD
=
r
;
(like vertical ones). Consequently, From the equality of triangles we see that CB
=
AD
.
Since O
the center of the circle, then the chords passing through it are divided into equal sections.
We get: AB
=
AO
+
OD
.
Find the perimeter of triangle AOD
:
AB
+
AD
= 13 + 16 = 29 cm.
Answer: 29 cm.
18.
Two cars left A for B at the same time. The first one drove at a constant speed all the way. The second one drove the first half of the trip at a speed of 51 km/h, and drove the second half of the trip at a speed 34 km/h higher than the speed of the first one, as a result of which it arrived at B at the same time as the first car. Find the speed of the first car. Give your answer in km/h. Write down the solution and answer.
Solution.
Let the entire path be 2 s
km, and the speed of the first car
is v
km/h, then the second car drove the second half of the journey at a speed of (
v
+ 34) km/h. We get the equation:
The problem conditions are satisfied by the root v
= 68.
Answer: 68 km/h.
19.
There are 75 different integers written on the board. Each number was either squared or cubed and the result was written in place of the original number. What is the smallest number of different numbers that could be written on the board?
Solution.
Some integers can be obtained by squaring or cubeing three different numbers. For example, for the numbers –8, 8 and 4, you can square and cube them to get one number. However, no integer can be obtained in this way from four integers.
So, 75 numbers written on the board can be “glued together” in no more than three. Therefore, among the 75 results of exponentiation, at least 25 must be different.
Exactly 25 different results can be obtained, for example, if we square the numbers ..., and cube the numbers ..., In total we get 25 different numbers: ...,
Answer: 25.
Description
The iris family has many species, and aquarium conditions are quite suitable for all. The fish has an oval body, strongly flattened on the sides. The shape of the fins is interesting: the dorsal one bifurcates, one part is very small, the other is elongated. The anal fin is located symmetrically to the long part of the dorsal fin. The tail is forked. Almost all species reach sizes of 9-13 centimeters. Males are usually slightly larger than females. Under favorable conditions in the aquarium, iris will live fully from 4 to 8 years.
Compatibility
Despite their relatively large size, iris are peaceful and do not offend even relatively small neighbors.
The best company for rainbow girls would be:
- angelfish;
- swordtails;
- mollies;
- tetras.
Kinds
- Boesman's melanothenia . Since the areas where the fish live are quite limited, it is listed as an endangered species. At the moment, catching and exporting fish from the country is officially prohibited. The front part of the body is blue, with a slight purple tint. The back is orange. There is a smooth bluish border in the middle. The dorsal fin is orange with a greenish edging, the anal fin is yellow and blue. This colorful coloring is typical only for males; females are completely dark blue with a silvery sheen.
- Melanothenia three-stripe . The fish is distinguished by a variety of shades of color. It can be yellow, red, golden, blue. Its main feature is three dark stripes on the sides. The middle stripe starts at the mouth and reaches the tail. The lower and upper ones are less noticeable. The fins are colored scarlet and orange. The fins of the three-striped iris are scarlet and orange. In this species, females and males differ less well. Usually males are simply brighter in color.
- Melanothenia neon . The color of the body is pinkish-gray, with a beautiful steely sheen. Under certain lighting, the scales have a bluish tint, which creates an unusual neon effect. Males have red fins, while females have paler, yellowish fins. Melanothenia neon grows only up to 5-6 centimeters, which is why the fish is often called a dwarf fish.
- Turquoise iris . Another name is lacustris. Color varies from bluish to green and turquoise. At the same time, the scales have a purple tint. The upper part of the body is darker, closer to blue; near the abdomen the color smoothly flows into silver-yellow or green. A small longitudinal dark blue stripe stretches from the base of the tail. The fins are blue, with black edging. Females are slightly paler in color than males. This fish is considered one of the most beautiful representatives of the family.
- Parkinson's melanotenia . The main body color is steel gray. On the sides there are bright, like fiery flashes, orange spots, smoothly transitioning to the fins and tail. In this case, the tail and fins have a gray edging. There is a yellow variety, with corresponding spots. This coloring is also characteristic only of males; females are painted a solid steel color.
General information about neon iris
The neon rainbowfish, or neon melanotenia, is a ray-finned fish that lives in fresh water. Belongs to the Melanothenia family.
It gained its popularity among aquarists for several reasons.
- Bright and attractive color with mother-of-pearl and neon reflection.
- Active behavior.
- Gets along with various types of aquarium inhabitants.
- Reproduces quickly and easily even in captivity.
Neon iris is very popular among aquarists.
Unlike other members of the family, this fish has a very modest size, so it can often be called a dwarf iris.
Conditions of detention
In their natural environment, irisfish can exist at temperatures from 5 to 35 degrees. Aquarium fish are not ready for such a shock; it will significantly undermine their health and have a detrimental effect on their color.
The fish live in schools, so it’s better to have several, at least 6 fish. These swimmers will need a large aquarium - from 100 liters. The optimal choice would be a horizontally elongated tank of 40 cm or more, because Malanothenias do not like to swim vertically. The aquarium must be equipped with a lid - the fish are very jumpy and can easily end up on the floor.
Water requirements:
- Temperature – from 20 to 28 degrees.
- PH – from 6 to 8.
- DH- from 4 to 9.
- It is necessary to change a quarter of the water in the aquarium daily.
The tank must be equipped with an aeration system and a good filter installed. Lighting should be bright during the daytime. It is advisable to provide natural sunlight.
When choosing soil, focus on dark ones, for example, small pebbles or coarse river sand. Against such a background, the fish will look more impressive. Suitable decorations include driftwood, large stones, grottoes, etc. The main thing is that they do not clutter the entire aquarium - the iris should have enough space for swimming. There are no special requirements for the selection of plants. The fish are unpretentious and feel great next to most green spaces.
When setting up an aquarium, make sure that there are no sharp edges on the ground and decorations. Swift and active rainbows can easily get hurt by them.
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What to feed irises - melanothenium
The fish are completely undemanding when it comes to food and eat a variety of foods. Please note that feeding iris should be correct: balanced and varied. This fundamental rule is the key to successful keeping of any species of fish. Therefore, it will be useful for you to read the article “How and how much to feed aquarium fish,” which describes this in detail, and also outlines the basic principles of the diet and feeding regime for fish.
We recommend feeding them with high-quality and proven food from Tetra.
It would not be amiss to note that when purchasing any dry food, you should first of all pay attention to the date of its manufacture and shelf life, try not to buy food in bulk, and also store the food in a closed state - this will help to avoid the development of pathogenic flora in it .
Feeding
Feeding Rainbowfish do not have any special nutritional requirements. They eat food live, frozen or dry well. When preparing your diet, you should maintain balance. It should be remembered that the predominance of dry food can provoke various diseases. As for live food, all types of iris are excellent eaters of tubifex, small bloodworms, small crustaceans, and insects. It is imperative to include plant foods in the diet, otherwise irisfish will nibble on aquatic plants.
Does the diet of rainbowfish change depending on the time of year? The immediate answer is yes! An important factor is that the nutrition of iris in the wild differs in seasonal characteristics. What does it mean? In wildlife there are two seasons for fish: the dry season and the rainy season. Thus, during droughts they eat more plant foods. During the rains, on the contrary, it is “meat” food. What is this connected with? During the rainy season, life in the water becomes more active, more insects, fish fry, crustaceans and others appear. That is, it turns out that during drought, iris eat more plant foods, and during the rainy season, they eat more protein-rich, “meat” foods. This important fact should be especially taken into account if you are trying to get your fish to start spawning, since they reproduce only during the rains.
Nutritional Features
Under natural conditions, the neon iris feeds on animal and plant foods in large quantities. For normal life and development, it is recommended to provide her with a varied diet in an artificial environment :
- Rainbowfish do not take food from the water column, but collect it on the surface, so you should choose food that is light in weight and can stay on the water longer.
- To ensure that the soil does not become clogged with food debris and does not pollute the water, you can keep speckled catfish with melanotenia, which select food exclusively from the soil and will help in cleaning it.
- Among animal food, fish prefer small varieties of bloodworms or tubifex.
- Plant ingredients can be used to cook cucumbers, lettuce or zucchini. They use all this with pleasure.
An important condition will be moderation in feeding, since excess food leads to disruption of vital processes in the fish’s body. During spawning, the precox prefers animal food, at other times it can be content with plant food without harm to itself.
It is allowed to feed individuals with special dry mixtures intended for them. In this case, the dosage should be observed more strictly. This is due to the fact that such food takes longer to digest and can cause digestive problems for the fish.
How do they get along with each other and with other inhabitants of the aquarium?
If a novice aquarium fish breeder wants to acquire only irises, he will not go wrong. It is only important to take into account the ratio of males and females to the total number of the flock.
The nimble luminous fish scouring the entire water space of the aquarium look touching against the backdrop of the dark bottom and lush vegetation. They get along well with their fellow irises of other species.
However, wanting to diversify the living creatures, the aquarist can add the same peaceful, active and small fish to the neon melanothenia. The following are perfect for living together with rainbow babies: thornets and various types of barbs, angelfish and lalius.
In such company, dwarf iris will feel free, playfully swimming among the luxurious thickets. Well suited for keeping with small and peaceful fish in a community aquarium. This is a schooling fish and the male to female ratio is very important for breeding. If you keep them only for beauty, then males are preferable, as they are brighter in color.
Depending on the size of the flock, this ratio is better:
- 5 neon irises of the same gender
- 6 neon rainbows – 3 males + 3 females
- 7 neon irises – 3 males + 4 females
- 8 neon irises – 3 males + 5 females
- 9 neon irises – 4 males + 5 females
- 10 neon rainbows – 5 males + 5 females
It is best to keep a flock of 10 or more. Make sure there are more females per male, otherwise they will be under constant stress.
How to distinguish a male from a female
Males and females of the neon iris differ from each other.
This applies to both the appearance and behavior of individuals. Females are calm. They do not like active movement. They prefer to stay in areas with dense vegetation. They do not get into fights or clashes with other inhabitants of the aquarium. The color of the scales is bluish-pink, pale. Females have a rounded abdomen.
Males have distinct colors. The colors are saturated, a horizontal stripe runs along the body.
In females the color of the scales is pale, in males it is brighter
Males move actively, dance a mating dance, attracting a female. During the spawning period they can show aggression. They are inferior in volume to representatives of their species.
A flock of neon irises will be the bright spot in your aquarium. This fish is unpretentious in care and does not require special conditions. It feeds on foods familiar to aquarists. It is very popular and well studied.
Did you like the neon rainbow? Share your opinion about this fish in the comments.
Diseases
Despite all the convenience of keeping iris, they are often infected with mycobacteriosis and diseases caused by the activity of helminths. Fish affected by the disease are lethargic and lack appetite. The surface of their body, and especially the fins, are covered with mucous grayish spots, which gradually turn into open ulcers.
Over time, if left untreated, the infection can destroy the fins, causing the melanothenia to die. To fully understand the cause of the disease of the sweetest representatives of aquarium fish, you need to consult with a specialist who will advise medications and care rules.
It is extremely important to prevent the occurrence of diseases in iris. To do this, you should: systematically change the water in the aquarium and monitor the temperature, conduct constant inspections of the vegetation and the fish themselves, use only high-quality food, etc.
To prevent irises from becoming infected with bacterial diseases, quarantine measures . So, if a fungal coating is detected on the head of a fish, it must be removed using methylene blue and salt.
Diseases and their treatment
With proper maintenance, iris are almost not susceptible to disease, but if living conditions are violated, parasites and infections are possible.
In case of infection with skin parasites or fungal plaque: it is necessary to increase the water temperature (up to 28C°) and increase aeration. For skin parasites (their presence is indicated by swelling and ulcers on the body of the fish), add sea salt to the water for every 10 liters of water. After recovery, remove the salt by gradually replacing the water. For fungal plaque, add 3 ml of 1% methylene blue solution for every 10 liters of water.
Breeding
As with the breeding of other species of iris, the neon iris requires preliminary preparation for spawning and the presence of a separate spawning area. Before settling into the spawning area, the spawners are fed live food rich in protein, sometimes adding plant foods with spirulina. The bottom of the future nursery for fry should be lined with synthetic thread or small-leaved plants. Install the internal filter. Stimulation of spawning occurs due to an increase in water temperature within 26-28 degrees.
A couple of breeders lay eggs over several days, with each new spawning the number of eggs will increase. One clutch contains an average of 150 eggs. When the parents show signs of exhaustion, they should be placed in a community aquarium. After 6-10 days, the fry will hatch, the starting food for which is ciliates and liquid food for fry. Then you can add Artemia naupilia, microworms, and egg yolk to the diet. Precox fry grow slowly and become sexually mature at the age of 6-10 months.
Buying an iris is quite simple; these unpretentious and very bright creatures are available in almost every specialized store. And their cost on average is 100-150 rubles.
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Interesting Facts
Rainbow fish are considered one of the most beautiful inhabitants of home artificial ponds. But the brightness of their color depends not only on their state of health, it is also influenced by their mood.
If there is a stressful situation in the aquarium, then the entire flock immediately becomes dull. So these fish can safely be called a barometer of the psychological situation of the underwater environment.
But as soon as the adaptation period passes, the acid-base balance is leveled out, and the water temperature stops jumping, the irises immediately begin to shimmer with all the colors of the rainbow, especially in natural sunlight.
