Selective Breeding and Genetics for Angelfish
Introduction to Angelfish
First, this is an article about freshwater angelfish and should not be confused with how to care for saltwater angelfish.
This article will briefly touch on the genetics of angelfish and how to tell different subspecies apart. It will also discuss physical attributes and quality attributes of different species, or what makes a beautiful fish and what makes a not-so-beautiful fish. Further, the article will discuss breeding and how to sex fish, breed them, and care for their fry.
This article also accepts that fact that not everyone is able to acquire pure blood lines and show quality stock for breeding purposes. For that point alone, there is a discussion below about how to choose the best physical attributes from stock found in local fish stores.
The genetic information contained in this hub is based on the research and published work of Dr. Joanne Norton, who sadly passed away in 2005. Her remarkable work should be read in its entirety by anyone who wishes to breed these remarkable fish.
The wild angelfish is silver with three black strips. One stripe goes through the eye, one on each side of the dorsal fin. In the hobby, they may be called silver or even wild angelfish. In my opinion, they are perhaps the most beautiful of all the freshwater community cichlids.
Through selective breeding, the angelfish have become much like goldfish in that there are now a variety of subspecies that do not exist in the wild. Many of the subspecies of angels have multiple names but their underlying genetic makeup remains traceable through attribute and form. In short, one can tell a vast amount about angelfish by their looks. In the following paragraphs, I will go into some detail about the genetic code and how to choose fish for breeding. For many fish keepers, most of this article will be of little interest. The genetic section is primarily written for those people who are interested in breeding either as a hobby or for profit.
The Science of the Species
- Kingdom: Amilalia
- Phylum: Chordata
- Class: Actinopterygii
- Order: Perciformes
- Family: Cichlidae
- Subfamily: Cichlasomatinae
- Tribe: Heroini
- Genus: Pterophullum
Angelfish belong to the genus Pterophyllum. There are three basic subdivisions as binomial named within the genus Pterophyllum: Those are P. scalare, P. altum, and P. leopoldi. The binomial name specifically refers to geographic location of the wild fish. The Wild species are found only in the Amazon river, Essequibo River and the Orinoco River and or basins associated with each river. Make no mistake, Angelfish are a new world cichlid and as such can sometimes be cichlid like in behavior.
They are often sold in the aquarium fish business as community fish and for the most part that is a good spot for them. They are not as aggressive as a red devil cichlid or even a mild mannered jack dempsey, though a mating pair can wipe out a community tank. They should not be housed with other Cichlids (African or New World) with the exception of (maybe) Discus or Dwarf Cichlids such as Rams.
The Characteristics of P. Leopoldi
One of the key distinguishing factors to look for when separating out species of Angelfish is the pre-dorsal notch which is deeper on P. leopoldi. This pigmentation may include part of the dorsal rays or it may appear only on the body. Attitude is also an important characteristic of P. leopoldi, which happens to both the smallest and the feistiest of the three species. One of the easier or quickest ways to determine species (Though not always accurate) is to look at the facial build of the fish. The three wild types of fish have very different facial characteristics. For those hobbyists who are interested in breeding, this is an important consideration. A deeper explanation follows this paragraph.
The Characteristics of P. Altum
P. altum is found only in the quieter waters of the Orinoco River and the basins or the backwater Upper Rio Negro River. One of the primary identification factors for P. altum is the supraorbital indention or a notch that occurs on the slopped forehead which produces a slightly upcurved nose and mouth. Also common is a black or dark pigmentation that occurs along the body slightly below the 4th dorsal ray.
This is also largest of the wild species and the most difficult to breed in captivity. They require highly oxygenated water, and this is a challenge for keeping them in the aquarium. For those hobbyists who just want to keep Angelfish, an air bar or bubble bar that is one inch long for each ten gallons of your tank is required. This should be matched with an air pump that is also ten gallons per inch of air bar. A 30-gallon tank would need at a minimum a 3-inch air bar and a 30-gallon air pump.
pH and Temperature
The characteristics of water for both the Orinoco River and the Rio Negro have pH that range on the very low side: 4.5–5.8. Temperatures should never drop below 78 degrees F. and range from 78–86 degrees F. For those hobbyists who want to breed angelfish, the above characteristics should be paid close attention. These are not easy fish to keep, and the mixed variety that are typically found in fish stores should be avoided by the beginning hobbyist.
Further, The pH difference of P. altum requires quite a bit of pre-setup work. It takes time to get the pH in an aquarium to drop to 5.8, and I do not recommend the use of chemicals to lower pH. Once a tank is established at such drastically low pH, it is next to impossible to add new fish to it. Most if not all fish stores use regular tap water to fill their tanks, and regular tap water typically has a pH of 7.5 or above. Here in Sacramento, tap water has a pH of 7.8 and sometimes 8.0.
Adding a fish from a tank of 7.8 pH into a tank that has a pH of 5.8 will kill it. This means that several transitioning tanks will need to be used to acclimate the fish to a lower pH. Most fish can tolerate a wide range of water chemistry, but they must have time to adjust to the changes. Rapid change of environment will kill most fish.
The Characteristis of P. Scalare
Of the three species of wild species, P. Scalare is likely the most common to be found in the local fish store. Sometimes a mix of two species will also be found. For breeding purposes, these should be avoided. Since amateur aquarium keepers are often the most impatient of fish keepers, they breed whatever is available. One of the purposes of this guide is to help the beginning breeder to choose good breeding stock. I can not think of another fish that is more beautiful than a really well-bred angelfish.
pH and Temperature
The characteristics of P. scalare are a large forehead and rounded face that is much more rounded than either P. altum or P. leopoldi. Tank conditions are much more forgiving for keeping P. scalare than for either of the other species. This fish has a wide tolerance of pH that can range from 6.0–8.0. Water hardness can range from 5–13, and water temperature can range from 76–86 degrees F. Higher temperatures are usually breeding temperatures. People who keep fish should strive to have a somewhat constant set of water chemistry parameters.
This is also an angelfish that like to have dense vegetation. Plants that work well for this fish are Valisaria, and broad leaf Amazon Swords. A Broad leaf Anubia may also work well. The vertical strips on angelfish are designed to help them hide amidst the tall Val like plants found in their native habitat. I would also consider a blackwater product as a tank additive for any of the three angelfish species listed here and especially for P. scalare, which is often found in flood planes. Soft sand substrate will also work well for all angelfish.
For most of us, the concept of genetic is complicated. While not an expert in genetics, I will try to simplify these concepts so that other fish keepers can find the joy of not only keeping angelfish but to breed beautiful angels too.
Genetics, for the most part, is a sharing of traits during reproduction. The genetic code for all organisms is held in the organisms DNA. DNA usually consists of two sets of genetic code. I say usually because there are instances when the genetic code does not align correctly.
A good visualization of DNA is to think of a zipper. If you undo the zipper, you have two equal sides that when zipped together form a single zipper. The teeth on the zipper are the genes and the attributes of each gene is an unknown and remains an unknown without genetic mapping. Genetic mapping is a topic for another hub. What is not unknown and is of importance to breeders (and fishkeepers) are the developed physical attributes of adult angelfish. We know that by breeding certain angelfish with other specific angelfish that the results will be a mixture of the two genetic codes.
Genetic Symbols and Common Phenotypes
Genetics: Passing Traits
Each organism is comprised of a set of genetic code from its mother and its father. The development of physical characteristics is a matter of dominant genes verses recessive genes. This is the part of breeding angelfish where the breeder must decide on the physical attributes that the breeder values, and then choose those attributes through the process of selective breeding. Selective breeding only works though if the attributes being selective can become dominant. That is slightly different than saying a dominant gene because an attribute can be the result of two recessive genes. The goal is to breed for the attributes that the breeder desires.
Generalization of Genetics
To make things clear, we assign codes to a specific phenotype so that the phenotype can be tracked. A locus or its plural- Loci refers to the exact location of the gene on a strand of DNA. An Allele is one of two or more (a group of) genes that may be housed at a specific locus. Dominate refers to one of two or more genes where one specific gene is "Chosen" 100% of the time over the second gene (recessive.) A Gene that is listed as a lowercase letter (g) (z), etc is recessive, and genes that are listed as capital letters (D), (Z), (G) are dominate.
Phenotypes of angels fish maybe separated by a (/) slash as a means of listing multiple genetic code associated with some of the more complex sub species of angelfish. D/D - Gm is an example of a set of code where the D/D is one parent and the Gm is the second parent. I will explain more about this in the following paragraphs.
The Basic Genetic Idea
Refer to the Table above Titled Genetic Symbols and Common Phenotypes:
The basis of genetic is that like breeds like... and when it does not then the genetic line is NOT pure. Never expect to find a pure genetic line from stock that you find at a local fish store. If you want a pure line, then you must purchase from a reputable breeder.
The basic of genetics is that each gene consists of two parts. One part from the father, and one part from the mother. The Capital letters mean the gene is dominant. A dominate gene will exhibit its trait over a recessive gene. The lower case letters are recessive. With Symbols, the bold symbols are dominante, and the regular symbols are recessive. So an angelfish that is a purebred domestic silver would be coded as +/+, where the first + is the mother, and the second + is the father. If the same fish had a mother that was a pure bred domestic silver (+/+), and a father that was a half-breed domestic silver crossed with a Dark Angel (+/D)... This is important because the offspring of this pair will have one in four chances of being...
(+/+) (+/+) (+/D) (+/D)
If the mother was a +/+ and the father a D/D then the offspring would all be (+/D)
If the Mother were +/D and the father were +/D than the offspring would be...
(+/+), (+/D), (+/D) or (DD)
It is likely in this case that 50% of the offspring would be (+/D) and 25% of the offspring would be (+/+) and the remaining 25% of the offspring would be (D/D.)
Genetics do not just affect coloration of fish, they represent the physical and inherent traits that show up as phenotypes. Albinoism is one such phenotype that is not specific to coloration as is temperment. Remember that fish have a long list of genetic codes... the codes in the table above refer to color... but body shape is also a genetic code, fin structure is another genetic code, and the list goes on.
In the fish store, what you look at is always a guess, but you look for those fish that present the characteristics that resemble a pure bred angelfish of that specific phenotype... Gold Marble, Dark, Zebra, etc. This only works if you are breeding for the local fish store and not for show quality fish. Show quality fish must come from a reputable breeder and likely for several different reputable breeders so that you ensure you are not breeding brother to sister. I say this because there is money to be made breeding quality angelfish... so long as what you breed is beautiful. They do not have to be genetically pure...but they need to be beautiful.
The Sunset Koi Angelfish
The above picture titled Sunset Koi is an okay example of what a sunset koi should look like. In terms of genetic make up, the fish in the picture is not a true sunset koi. This is important if one is shopping for breeding stock.
Choosing the best stock is key to breeding beautiful angelfish. Understanding how genes are displayed physically will help the breeder to choose the best fish possible. When choosing fish, select fish from different sources to help ensure that breeding stock is not related. Never breed siblings. The short term result will produce very odd and very undesirable fry... many of which will need to be destroyed.
Physical Attributes and Genetics
Select breeding is the art of isolating specific traits, usually physical traits, but can also include temperament, longevity, etc. In Angelfish, most breeders use selective breeding to isolate specific physical attributes such as color, markings, scale texture or color.
To begin selective breeding, you must decide what attributes interest you and then determine what your goals are to achieve those attributes. This is how we develop a breeding program. To develop a specialized breed of angels requires time and space and a great many tanks. Selective breeding is very different from just breeding angel fish. The methods used for selective breeding will be covered in another article.
Using the concept of selective breeding to breed quality angelfish is the focus of this article and for many breeders worldwide, developing a quality breeding stock also takes time and space, but once that has been achieved the market for your fish can become quite lucrative.
Aggression is never a pleasant trait in fish, especially fish that are going to be classified as community fish. Do not breed angelfish that are aggressive unless you can breed the aggression out of them. They may be beautiful, but that is canceled out if they kill everything they are housed with. Remember that angelfish are also cichlids, and cichlids can be very aggressive. Choose mild mannered fish for breeding.
What Makes a Beautiful Angelfish?
Fish in general have always captivated me, but Angelfish are probably one of the worlds most beautiful fish. Sadly, what we find in local fish stores are usually the middle of the class and rejects from larger breeding programs. That is not to say that these fish are not beautiful because most of them are, but they are not the top 10% of the brood that were potentially show quality fish.
Beauty, they say, is often in the eye of the beholder. For local breeders this poses a small problem, small being the key word. Many of the traits of these fish are hidden when they are small, juvenile, or fry. It is not until they are an adult that many fish can be adequately judged.
We can discuss some of the traits here that make up a nice looking fish. These traits can be judged when the fish is small. Most fish stores offer small and juvenile angelfish for sale. I would also recommend buying most angelfish as dime size, quarter size but no larger than a fifty cent piece. Larger angelfish are usually more aggressive than are the juveniles.
The body of an angelfish is one of the key features that breeders should look for. The body should be as round as possible and taller than it is wide. The tallness should begin where the dorsal fin begins and end between the pectoral fin and anal fin. Avoid fish that are not circular in shape or that are elongated. The body shape can be identified when the fish is small.
The fins of angelfish are what gives them grace and beauty. Fins should be straight, free of curves, twists and blemish. It is important to look carefully at all of the fin's edges. the thin membranes should be intact, straight and free of breakage. Avoid fish that have ragged looking fins, short fins, or blemishes in their fin. These do not make good breeding stock because the cause of the visual defect can not be linked to either a genetic cause nor an environmental cause.
Coloration is very difficult to judge in angelfish because so much of their coloration is caused by environmental influence, stress, and/or genetics. Rather than focus on color, focus on the quality of the body and the quality of the fins. What you do want to focus on in coloration is that lack of color, pigmentations and hue. Any angelfish that is chosen for breeding stock should be isolated or kept in small groups until the breeder is certain that their coloration is environmental.
Stress, choice of food, and other criteria outside of the fish's control can lead to dull coloration. If you bring a fish home to breed, give it the best food, the best environment and watch to see if color improves. If color does not improve then do not breed this particular fish. It may still be beautiful, but what you are seeking in terms of your fry is vibrant coloration, perfect bodies, and excellent fins.
The dull color of a gold cap angle is not a bad thing if the body and the fins are perfect. What you want to look for in this case is not the color but the lack of stripes, dots in the fins, and otherwise color blemishes that would detract from the starkness of the gold cap angel. The same is true of any angelfish that is to be without stripes.
Dull coloration in a koi angel is also not a concern if the body and fins are perfect. What you want to look for in this case is the beautiful marbling that occurs without the hint of stripes, including stripes in the fins.
When selecting fish that are striped, such as the Zebra Angelfish than look for crisp stripes that have edges that are pure lines, without indentations or breakage. The lines should be continuous and roughly the same width.
How to Breed Angelfish
Breeding angelfish is not difficult. What is difficult is breeding angelfish successfully. There are many problems that can occur between mating and hating of fry. One of the common cause of failed breeding is the result of fungus. Stress is also another issue that breeders must help their pair overcome. The first thing to know about breeding angelfish is that is usually takes a pair of angelfish several attempts at raising fry before they are successful.
Setting Up the Best Breeding Tank
Many people may argue that a breeding tank should be small, ideally around 20 gallons. I say the tank should be large, ideally a 55 gallon, 75 gallon or even a 90 gallon. My reasoning is as follows. Larger volumes of water stay healthier longer. Smaller volumes of water become toxic faster. It is difficult to do water changes in a small tank when Angelfish have spawned. It is much easier to do water changes in a larger tank where angelfish has lain eggs without disturbing the parents too much.
Medium gravel that has been in the tank for a minimum of 3 months. It should be easily cleaned using a gravel vacuum. I don't recommend sand unless the tank is heavily planted and that does not always work well in a breeding environment.
- Two large spong filers rated at 55 gallons or larger.
- Two 30 gallon heaters for 1-55 gallon tank, or two 50 gallon heaters for 1-90 gallon tank. Heaters should be placed at opposite ends of the tank.
- Hood with plant lights.
- 1 large potted broad leaf plant (live vs plastic), or 1 6-8 inch diameter tera cotta pot, or a 1 gallon (VERY CLEAN) glass jar.
The tank should be set up and run for a minimum of 3 months before attempting to bred angelfish.
- Place 1 sponge filter at each end of the tank.
- Place 1 heater at each end of the tank about 10-12 inches from the sponge filter. Heaters should be set at the same temperature that the parent angelfish tank is set at. Once the parents have been introduced to the tank you can begin to bump up the temperature 1 degree per day until the tank is at 86 degree. Do not turn the heat up and then put the adult angels in, the temperature change will shock them and they will likely die.
- Place the large potted plant or the large pot/jar in the center of the tank. When you introduce the parents to this tank, make sure that the lights are low or off. Allow the tank to receive day light but not bright overhead light. This is why plant bulbs work really well they are dim but provide light.
If the eggs repeatedly turn white and the angelfish parents eat them, then it is likely that the eggs are developing fungus and dying. To combat this use Methylene blue. Follow the manufacturers instructions.
How to Care for Angelfish and Fry
When I breed cichlids I feed them live brine shrimp and live tubi-flex worms. I also feed them three to four times per day. The food rich environment seems to induce breeding. The larger tank also allows them the room to spawn without messing with their territorial instincts.
There are commercial fry foods available. First Bites is one such product. If you are breeding for profit, then think about using natural foods that are cheaper. You can easily grow your own daphnia, but I use boiled egg yolk and algae wafers to feed my wigglers, and small fry. Fry will also feed off of the sponge filters. Freed fry up to 6 times per day... but only what they will eat quickly. Using egg yolk works well... and it is cheap, high quality protein, and simple to make. Simply boil an egg, discard the white and keep the hardend yolk. To use: place some boiled yolk on a spoon and gently swirl the spoon in the water near the fry. This should result in an egg yolk cloud which the free will devour. You can also crush up a quality flake food... though... that is not my first choice.
To help keep the tank clean you can use snails . . . common aquatic plant snails work well and should not bother the eggs. I keep a tank of them on hand whenever I decide I want to breed fish. Water changes should be done 1 time per week at 10-20 percent volume of water change. Gravel vacuum the ends of the tank but leave the center alone. If the ammonia level, in the tank begins to rise add more snails and increase water changes to 2 times per week.
Angelfish and Fry
Breeding for Profit
Breeding animals and fish is a responsibility. That responsibility is not just to the creatures that you are breeding but to the society that will be impacted by your breeding program. Before you engage in a fish beeding program, whether that is Guppies, or Angelfish, make sure that you have a market that is secure.
- Check with your local fish stores and find out which ones will buy fish from the public.
- Do they pay cash or give in-store credit for fish they purchase?
- Understand how many fish they are likely to buy in a month.
- Check for local fish clubs.
- Do they have a set up for selling and trading fish?
- Check the private sector. Many private individuals will buy fish directly from you if your fish are of high quality.
- Be prepared to separate breeding pairs or destroy eggs when the demand for fish is not high.
- Understand the pricing structures of local fish stores. Base your prices on wholesale not retail. If the local fish store sells Juvinles for $8, then expect they will buy yours for $.50-2 dollars at most. They may pay more if they can see the quality of your stock.
- Check and develop a list of companies that supply fish on a wholesale basis. Many of these may buy quality angelfish. Fish can be shipped relatively easily if bagged and boxed properly.
Breeding for Profit
A breeding program requires up to five fish tanks for one batch of fry. Fry must be sorted as soon as possible into grades. Because breeding stock are from a local fish store, not every fry is going to be beautiful. That is ok and expected. Be prepared to sell undesirable fry when they are small... nickle sized is good.
The remaining fry must be housed, fed and cared for, because they are your true investment. Allow those fry to grow to quarter size and then separate them again. The bottom 50% can be sold, and the remaining 50% further divided into Fish that you want to keep for breeding, the best of the best, the best and the fry that will be sold next. Usually breeders that are not trying to selectively breed a new strain keep very few of their fry...1 or 2 of the very best fish possibly.
The larger the tank that they are kept in the faster the fry will grow.... this is of course dependent on their food and feeding schedule. Grade them by size. Dime sized are fed 4-5 times per day, Nickel sized can be feed 3-4 times per day. Quarter size should be fed 2-3 times per day. Fifty Cent sized angels should be fed 2 times per day. Feeing your angelfish is essential to maintaining healthy stock, preventing disease and providing the best environment for your fry to display coloration.
Aggression: Aggression is never a pleasant train in fish, especially fish that are going to be classified as community fish. Do not breed angel fish that are aggressive unless you can breed the aggression out of them. They may be beautiful, but that is canceled out if they kill everything they are housed with. Remember that angelfish are also cichlids, and cichlids can be very aggressive. Choose mild mannered fish for breeding.
Angelfish should never be housed in a tank environment that is less than 3 months old. Set up and run an angelfish tank for 3 months before adding angelfish to the tank. Use a small group of tetra to season the tank.
Keeping Angelfish at Home: Non-Breeding
Keeping angelfish in a home aquarium is not quite as easy as it is to keep Guppies. Angelfish can be sensitive and fragile. Minimum tank size should be no less than 55 gallons. Here, are some tips to help keep angelfish successfully.
- Tank: Use quality filtration. I would recommend an undergravel filter instead of the traditional piggyback filter. Medium sized substrate OR-
- In a heavy planted tank, use sand, plant substrate such as florite, and a canister filter.
- Heater(s) to keep the tank at 84-86 degrees.
- Driftwood should be use in conjunction with crushed coral gravel or a mixture of crushed coral gravel and regular (medium sized) gravel. Coral raise pH while driftwood lowers pH.
- FEEDING: Feed twice a day a mixture of live food and quality flake food. Avoid pellets. Feed only what the fish will eat in three minutes of time.
- Maintenance: Expect to do 1-2 10-20 percent water changes per week. Angelfish are very susceptible to poor water quality. Keep all water chemistry at 0 ppm and pH between 6.5-7.0.
Ideal Aquarium Plants for Angelfish
This is a complex article. If you have questions please feel free to ask. I am happy to share my knowledge with readers.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.