Developmental Color Change in Goldfish

My fancy goldfish, Rashi, was purchased as a black Moor. However, over the years she has been slowly turning orange. In an effort to understand this transformation, I have done a bit of reading about colors in fish and why and how they change, and I would like to share some of my findings with other curious fish owners.

The colors of fish are due to the presence of pigment cells called chromatophores. Chromatophores come in two varieties: those that absorb light and those that reflect light. Some light-absorbing chromatophores that occur in fish are melanophores, erythophores, xanthophores, and cyanophores. Leucophores and iridophores are examples of light-reflecting chromatophores. Inside chromatophores are organelles called chromatosomes. The type of chromatosome found in a chromatophore determines the color of the pigment cell. For example, melanophores, which are black, contain melanosomes, ie. melanin (black) is the pigment in the chormatosomes of melanophores.

Scientists have identified two types of color changes in fish: physiological and morphological. Physiological color changes are due to the spreading out or aggregation of chromatosomes. When the chromatosomes are spread throughout the cell, the color is more pronounced to the naked eye. However, when the chromatosomes aggregate in the center of the cell, the color is muted or not visable. Morphological color changes, on the other hand, are due to a change in the number of chromatophores. So a fish that loses a number of melanophores will appear lighter, and a fish that gains melanophores will appear darker. Physiological color changes can become morphological color changes over time. For example, a fish that is kept in a tank with a dark background and dark rocks will become darker, initially because of movement of melanosomes in the already exisiting melanophores. However, if enough time goes buy, the fish will start to produce more melanophores and then the color change is considered morphological.

The common phenomenon of black goldfish turning orange, or young goldfish losing black markings as they grow is an example of a morphological color change. As the fish mature, they lose melanophores in a process called apoptosis. Apoptosis is directed cell death, or cellular suicide, and is an important phenomenon in many aspects of development. However, the exact molecular cues that tell a cell it's time to die are still very mysterious. In addition to apoptosis, goldfish that lose black coloration are also supressing the birth of new melanophores. The loss of melanophores reveals the other pigment cells present in the skin. The type and extent of color change a young fish will go through depends on their individual genetic makeup, and there is a lot of variation between individuals! Some fish even go through a second color change from the destruction of xanthophores (red pigment cells).

My Moor/telescope goldfish, Rashi, has been undergoing a very slow morphological color change over the last three years. When she first came into my life, in the spring of 2003, she was all black with a hint of orange on her belly. This picture is from July 2003:

Slowly the orange coloration spread as melanophores died and were not replaced. Here is Rashi in February 2006:

The rate of color change in Rashi is definitely not constant. Rather, she appears to go through bursts of change. Her coloration will remain stable for a few months or more, and then suddenly I will notice new orange patches on her. Here she is about a month after the above picture, in March 2006. Already the orange has spread further up her body.

Her coloration stayed like that pictured above until early May 2006, when I noticed new orange spots on her head.

Rashi has an on-going issue with mysterious spots on her tail fins. In hopes of diagnosing her, I took a small sample from the tip of her fin and looked at it under a microscope. While I was unable to determine what the spots are, I did get some interesting pictures of chromatophores. Here you can see the black melanophores and orange erythrophores.

To the naked eye, the fin appeared black. It is interesting to note how the melanophores in the above pictures appear to have more processes radiating from their centers than the erythrophores. This is indeed what we would expect to see in a black fin. As the fin changes from black to orange, however, the melanophores will retract their processes before they are destroyed. There have not been any reports of other light-absorbing pigment cells changing in this manner.

At GAB, we have a couple of reports of Moors turning orange as they grow, as well as orange Ryunkins and telescopes turning white, and calicos of various breeds loosing their black markings. Some of these goldfish have changed color within a few months while others, like Rashi, take a few years. Do you have a coloring-changing goldfish? Please share his or her story with us!

Sexing Goldfish

Sexing goldfish is very difficult before they reach maturity. Sometimes people can tell by looking at the shape of the vent. Females may have rounder convex vents while males have thinner concave vents. The pectoral fins of males may be rather thick and stiff (compared to those of female goldfish) and with a more pronounced outer ray. Some people also believe that male goldfish have longer pectoral fins that do female goldfish.

The following pictures will help you determine the sex of your mature goldfish. Thanks to Bludusty, Mikroll and EbayJo who contributed excellent pictures to this project.

Breeding Stars or Breeding Tubercles

Male goldfish will develop breeding stars on their gill covers (aka operculum) and along the first ray of their pectoral fins when they reach sexual maturity.

Below are pictures of a male calico shubunkin goldfish with breeding stars on his pectoral fin and operculum (pictures by Bludusty):

Male with breeding stars on pectoral fin and operculum:

This picture of Mikroll's red capped orandas shows the stars and thickening of the pectoral fin of the male (compared with the female). The female's body is also more rounded than the male's.

Vent

When goldfish are ready to breed you can observe changes to their vent area.

Below are pictures showing the vents of two mature male goldfish. The male vent is longer and is indented (concave). This is a lot easier to observe on a mature fish who is ready to spawn. (Pictures by Mikroll and Bludusty):

Below are pictures showing the vents of two mature female goldfish. The female vent is not as long but it is protruded (i.e. convex):

Behavioral changes

It is the female that really 'controls' the breeding. A female goldfish (not ready to breed yet) will send out pheromones (a type of steroid) which will encourage males to produce the milt. When the female is ready to breed she will release another type of pheromone that stimulates sexual behavior in the male. The male will react by checking out the females, nudging them in the vent area as you can see on this picture (Picture by Bludusty). Males may exhibit this behavior before the females are ready as well, but it will be fairly intense once the female is prepared to spawn. Once spawning starts the males will chase and bump the female until she releases her eggs.

The End Result

The female should release eggs that will look like these (Pictures by EbayQueen).

Goldfish in tanks will eat the eggs just like the black moor in the video, so if you want to raise fry you will either have to remove the eggs or the parents. Here is a picture of a 19 day old goldfish fry (picture by Mikroll).

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African Grey Parrots

14 inches ( 36 cm ). Male and female. Overall color, gray; feathers on crown, forehead, nape, neck, and throat have lighter colored margins. Bare skin around eyes, whitish; tail, red; bill, black; feet, gray. The Timneh parrot ( P.e. timneh ) which like the Congo form (P.e. erithacus ) is commonly bred, has a horn-colored upper mandible and brown to russet tail feathers. It measures only 12 1/2 inches ( 32 cm ) and is clearly smaller than the Congo variety. Distribution in the wild: Equatorial Africa from the Ivory Coast in the west to western Kenya in the east, and south as far as northern Angola, southern Congo, and northwestern Tanzania. The gray parrot's distribution is largely identical to the range of the African oil palm, the fruit of which forms the bulk of the bird's diet. Habitat in the wild: Forested plains. Birds forage in sparsely wooded savannas, and open country. Occasionally, they are also found in mangrove swamps.

These guys are the Einsteins of the parrot world. African Greys are not only great talkers but have proven that they can actually understand what they are saying, as proven by the late great Alex.

African Greys need a very loving and attentive human companion. They need to be kept mentally active and challenged. Without a good bond and relationship with their human companion most Greys can become aggressive, withdrawn, and phobic. Boredom and a lack of intellectual stimulation and variety can make for a pretty miserable life for these intelligent birds. Their noise level is in the moderate to high range which makes an African Grey not a good choice for apartments, condos, or people with easily annoyed neighbors. If I were to venture a guess I would have to say that most African Greys kept as pets are of the Congo subspecies. The smaller darker African Grey Timnehs are just as good of talkers as their cousins the African Grey Congo and seem to be gaining in popularity. So the word is out: African Grey Timnehs are pretty cool birds too. A good mix of fresh veggies and fruit along with a pelleted diet, and a high quality nut and seed mix will keep your grey healthy and long lived. Minimum cage size requirement for these birds is 34" x 24. Make sure you have lots of toys to keep them stimulated.

Amazon Parrot

An Amazon parrot is a large parrot of the genus Amazona native to the New World ranging from South America to Mexico and the Caribbean. Most Amazons are predominantly green, with accenting colors that depend on the species and can be quite vivid. Amazons, like all parrots, are zygodactyl, having four toes on each foot—two front and two back. They feed primarily on nuts and fruits, supplemented by leafy matter. Amazons are talkative, colorful, clever, bratty and sometimes considered a handful, but there are some subspecies that defy commonly held beliefs about the Amazons. There are 27 subspecies of Amazons found through-out the world. The most common species kept as companion pets are the Yellow-Naped Amazons, Double-Yellow-Headed Amazons, Blue-Front Amazon, and the Yellow-Crowned Amazons. All four of these subspecies are great talkers, but they can be loud and demanding as pet, and may have a tendency to become a one person bird. Some people like their "in your face" attitude and some don't. Either way, Amazons do command a presence no matter how you feel about them. This said, be very aware about what you are taking on when you decide on a Amazon as a companion pet.

Some of the smaller Amazon subspecies may be a little better to live with, such as the White-Fronted Amazon, Red-Lored Amazon, and the Lilac-Crowned Amazon. These smaller subspecies of Amazons are generally quieter, easier to handle and not quite as pushy as their larger cousins.

The life span of Amazon Parrots kept as companion pets has greatly improved over the years because we now have an understanding of how they live and survive in the wild and what it takes to keep these birds healthy. Unfortunately lousy care and poor diets still exist out-there and can shorten these birds lives by upwards of 10 to 20 years. Feed your amazon a well balanced diet of fresh veggies and fruit, a high quailty nut and seed mix, and a good pelleted blend. Minimum cage reguirements for an amazon is 24" x 22", but bigger is sometimes better. Please remember amazons can become perch potatoes, so have lots of wood for them to chew and toys to play with. Exotic birds should never be bought on impulse. Please research any bird you're interested in purchasing before you buy. Educating yourself can only be beneificial to you and your new companion parrot.

Finches

Garrie Landry breeds exhibition-quality Zebra Finches. He has over 30 varieties of zebra finch in his aviary. Visit the Acadiana Aviaries website to see photographs of his beautiful birds.

What should a beginner specifically look for in these birds when selecting initial breeding stock for exhibition-quality zebra finches?

Size is important and perhaps most important, as it is more difficult to increase size if it is not there to begin with. Conformation and carriage are equally important but these too can be dealt with after size. If sizeable birds are available, then among them look for birds that have a good shape and good stance. Choose those with the best markings too, such as males with a prominent breast bar and females that have no extraneous markings that resemble male zebras (i.e., no residual breast barring on the female).

What characteristics should they avoid when selecting birds?

Avoid skinny necks, droopy wings, or long beaks. Avoid thin breast bar markings on males. Choose birds that have a prominent tear drop mark, and birds with an overall "full" round appearance.

What diet do you feed your zebra finches?

I feed a standard finch seed, which is perfect for zebras. I also feed some spray millet as a weekly treat. During breeding season I provide a commercial nesting food or egg food to parents with chicks. And of course I supply lots of calcium to parents that are laying and raising a clutch; I use crushed egg shell from a local restaurant as my source of calcium.

What nesting materials do you find most suitable for zebra finches?

Zebras will use anything, but I prefer dried hay or grasses for this. I select thin bladed hay or grass for this purpose. Do not use lawn clippings that have not been properly dried. Grass is best. Avoid string and cotton as they will entangle the legs and feet.

Please tell us about your particular favorite mutation, and how this color was achieved? Are they easy or difficult to breed?

The Black Breasted Zebra is my favorite, as I looked at photos for so long before I actually owned any. It was developed in Europe but did not reach the US for nearly 30 years after it appeared. They are not difficult to breed but quite variable in color, so breeding a well marked one is a challenge.

For those who want to leap right into the mutations, are there any pitfalls you would like to warn them about? For instance, which mutations should not be put together?

Avoid mixing pied zebras with other mutations, as the pied can and often does ruin an otherwise well marked bird. Pieds are nice but pied is a frequent fault if it occurs in other colors. Do not breed Fawn cheeks or Grey Cheeks together as there is a tendency for the young to be blind. Since both genes are dominant always mate them to Greys or Fawns for the best results. When breeding for show quality, keep the family lines pure and do not introduce smaller birds as it will take a long time to rebuild size in the offspring.

People who have zebra finches seem to absolutely adore these birds. What is it that makes zebra finches such an attractive and loved species?

Most people like zebras because they are so easy to keep and easy to breed. It makes finch keeping a worthwhile hobby because you can see the family grow. They are charming birds and I personally like all of the different colors and varieties that I work with. It's a never ending challenge to combine them and make a new and different zebra color.

What do you think about the never ending quest for larger birds? Is it time for the show standard to have a specific size included in it?

Already many judges are disqualifing birds that are too large. So yes, to some extend a huge bird is not a better bird. Size still dominates the quest in some regions, but in others it is not the single-minded goal, and conformation to a standard is more pursued. It will probably be a while before standards have a size limitation in writing, but this issue is already being discussed.

A UK exhibitor writes that he has found that the bigger the bird the poorer the fertility. Have U.S fanciers had this problem as well?

Yes, beyond any doubt the largest birds are the poorest breeders. While some are good breeders, it is a minority. Fertility is not the only problem with larger birds here; in some cases breeding depression is prevalent.

In exhibiting zebra finches, how is condition of the bird weighed vs. other features?

Condition is certainly an important feature and a bird in poor condition should never advance in show. I cannot say that it is weighed more heavily than type and conformation, but it is probably more critical.

In the UK zebra finches are shown in pairs. Will this ever be the case in the US?

Nearly all zebra finches are shown as singles. It is very rare to have them shown in pairs here in the US. It has never been popular or required to show a pair, nor do U.S. judges care to see pairs in a cage. Individual birds are judged on their merits alone not with a mate. I personally like the idea of one bird per cage over showing in pairs only.

Rose-Breasted Cockatoo

Galah or Rose-Breasted Cockatoo

The cockatoo family comprises a large group of parrots from the continent of Australia. Species commonly kept as pets range in size from the small Goffin's to the large Mollucan or Salmon-crested cockatoo. The appearance of the various cockatoos varies dramatically, from the all-white Goffin's to the striking Black Palm with the splash of red between the eye and beak. One of my favorite cockatoo species is the rose-breasted cockatoo, also known as the Galah cockatoo. I remember the first time I handled one of these birds. I was astounded at how soft its lovely light grey and pink feathering was. Although the rose-breasted 'too belongs to the genus Eolophus, this genus is very similar to the genus Cacatua, the one most associated with the common term "cockatoo."

The rose-breasted cockatoo is a bit larger than the Goffins, usually around 12 inches in length. They have the typical crest on the top of the head that they fluff up when excited, although it is denser than on many cockatoo species.

Diet is an important consideration for all cockatoo species. Just like cockatiels and budgerigars, also Australian species, they are prone to fatty tumors and therefore need to be on a well-balanced diet that is not too high in fat. It is best to limit their intake of such fatty seeds as sunflower, although you can give them on occasion as a treat. It's important to get these birds to eat vegetables and grains so they do not overeat seeds.

Most cockatoo species love to chew. Therefore, take this into consideration when buying toys. Make sure they have plenty of wood to chew on, and don't let your furniture become their chew toy of choice.

Another thing to keep in mind when choosing any cockatoo as a pet is the fact that these species produce a powder they use to clean their feathers, just like cockatiels. People who tend to be allergic to animals may very well find this powder irritating. Many parrot species do not produce this powder, and a person who tends to have allergies would do best to consider something other than a cockatoo as a pet.

In the wild these parrots nest in the hollows of trees. They are, unfortunately, often killed as pests in Australia by farmers who don't want them to raid their crops. While they are not considered particularly endangered in Australia at this time, they are not as easy to find as pets as are many other cockatoo species. They tend to be quite expensive and they require a very large cage to get sufficient exercise, another way to keep down weight and avoid fatty tumors. As pets, rose-breasted cockatoos can learn to mimic, but they are not known to be great talkers. Properly socialized, hand-fed babies can be very gentle and sweet. If not handled regularly, they can become quite timid. Like all parrots, they are flock creatures by nature, and need to be in a central part of the home where they can interact with their human family.

Canaries

Origin: The Canary Islands. These islands were named by the Romans, after the packs of wild dogs which roamed them. The birds were named after the islands centuries later, not the other way around, as many believe.

Family: Fringillidae (finches), Genus: Serinus, Species: Serinus serinus (European serin finch), Sub Species: Serinus canaria.

Types

Song Canaries: Perhaps the most famous canaries of all, these are bred strictly for their song. Most are yellow, green, or variegated. Best known are the Rollers, Waterslagers, American Singers, and Timbrados.

Type Canaries: These canaries are bred for their shape, stance, or some other physical characteristic. Some well-known type canary breeds are the Fife, Border, and Gloster canaries. Rarer are breeds like the Lizard, Yorkshire, Norwich, and Frilled (which is also seen in many varieties). While some can be fairly free-singing, little to no attention is paid to the style or quality of the song by most breeders.

Color Canaries: These canaries are bred for the colour of their feathers, and range from the yellow-and-green colours of the other breeds, to more esoteric shades of bronze, vermillian, silver, and pink, including almost every hue except true blues and solid black.

Bilbo (left) is a non-intensive Consort Gloster canary. He is the type of bird who is bred to the crested canaries to produce both crested and non-crested Glosters. The crest is a dominant mutation, and a crested canary should never be mated with another crested. Flame (right) is known as an intensive Red Lipochrome Colour Canary, also sometimes called simply 'Clear Red', or just 'Red Factor' - although this last is actually more of a generic term, and properly applies to all canaries capable of expressing red colour in their feathers. *Photo by Michael de Freitas

Unlike many species of birds commonly kept as pets, canaries are territorial rather than social. The song of the males, and, to some extent the hens as well, is used to announce their presence and their claim to their territory. They are not very social with others of their kind and will rarely if ever enjoy sharing a pet-style cage with another bird.

Cages: Canaries are flyers rather than climbers, and therefore require larger cages relative to their size than many of the hookbills. Round cages should never be used with any kind of flying bird the shape makes it difficult to place perches parallel to each other, and so restricts the birds, making it difficult for them to move naturally. Bar spacing can be as much as 5/8 of an inch for the larger canaries, but should be no more than 1/2 an inch for the smaller breeds.

Diet: Like most other cage-birds, the canary requires far more than just seed alone. A basic seed mix should consist of 75% canary grass, 15% canola rapeseed, and 10% mixed specialty seeds such as flax, hemp, niger, and teazle. As much as 50% of the diet can consist of fresh foods, especially greens in the cole families mixed with grated carrot. Feed 'treats' such as millet sprays and 'song' food mixes sparingly and infrequently - they are very fatty and can stress their livers and kidneys if given too frequently. Clean, fresh water must always be available. Due to their small bodies and high metabolic rate, a canary will die within 12-24 hours without it.

Health: Canaries are extremely sensitive to trace gases and other such toxins, so be careful to not use air fresheners, rug deodorizers, perfumes, and other such volatiles in their presence. For this reason, the kitchen is not a good place to keep them; fumes or smoke from cooking foods could make them ill. Every bird-owning household should beware of Teflon cookware as this emits gases that are highly toxic to birds if overheated. Moulting should occur once a year, just after midsummer. A moult at any other time of the year is usually caused by the presence of a (warm or cold) draft from which the bird has no shelter. It can also be associated with shock or illness. A pet canary will usually live an average of 10 years or so, given good care.

Noise: Some of the type canaries can sing loud, rather shrill songs, but they are the exception to the rule. In general, the canary is one of the sweetest-voiced birds on the planet. Song canaries are trained to sing in harmony with others of their kind, and their owners compete vigorously for the prestigious prizes awarded their proteges. You can find quiet-singing canaries (Rollers), moderate-singing canaries (Waterslagers and American Singers), and loud singers (Timbrados, Type, and Colour Canaries). Rarely will canary owners receive complaints about the noise of their birds, which makes them particularly ideal for apartment dwellers.

Sleep: Canaries are photosensitive, and therefore should be kept on a cycle similar to that followed by the sun outdoors, unless you live in the tropics or at a pole. Many people cover their bird at sunset, and then remove the covers just before they go to bed, after the lights are out. That way the birds will see a natural sunrise. Don't allow their nights to be shorter than about 10 hours, or longer than 14 hours.

Sexual Behaviour: As the breeding season approaches, a hen will fly almost ceaselessly. She will begin to search for nesting material and trot about everywhere with beakfuls of it, looking for the best place to build her nest. When she is ready to mate, she will crouch low on the perch, with her head back a little and her tail lifted, and call the male with a soft, incessant twittering. She must be able to grasp the perch firmly, because she is the sole support for the two birds during mating.

The males will also become restless as the winter ends, and, if they come into full breeding condition early, may harass and chase the hens ceaselessly, stressing her beyond tolerance. For this reason it is best to cage the two separately but where they can see each other until the hen's actions indicate she is ready. Many males will feed their intended bride (or, if she is not accessible, the corners of his feet, or any other v-shaped niche in his cage), visually producing the effect that the birds are kissing. Divided breeding cages take advantage of this by allowing the male to court and feed his hen through the wire, but restricting his ability to chase her. Once the hen has indicated she is ready the divider is removed and breeding season begins in earnest.

Breeding: Canaries are photosensitive, and are brought into breeding condition by, among other things, the lengthening days of spring. They will fight ferociously with any other birds caged with them at this time, unless it is a bird of the opposite sex who is also in good breeding condition. They require soft foods with a good level of protein to feed the babies, who grow to adult size in less than 3 weeks. Weaning to independence is usually accomplished in another three weeks or less. Be warned if you would like to try breeding these small complex little beauties - unlike most of the popular pet bird species, canaries are anything but easy to breed!

Do your research thoroughly and well before you even think of trying to breed canaries. This aspect of breeding canaries is the reason you will rarely see a canary priced similarly to, say, a budgie; if you do, you should probably suspect the seller of harboring an unspoken motivation! Canaries hold a unique status in the world of songbirds, the little birds with the uncommonly beautiful voices, irrespressible personalities, and a long history of confounding humans. Perhaps that is why so many of us find them so irresistable.