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Tosakin Goldfish
Deformed Caudal Fin
Outline: Tosakin goldfish have a deformed tail fin, in which their double tail fin is joined. As a result their control and agility in the water is compromised. The effects on quality of life in a captive environment are hard to assess but it seems reasonable to conclude that they are negative. Research is needed in this area.
Summary of Information
(for more information click on the links below)
1. Brief description
The Tosakin goldfish has a large double tail fin that is undivided – as is usually the case in goldfish with such tails – and which spreads out like a horizontal fan in a half circle. It is quite unlike the natural tail fin shape and appears to be very ineffective at powering the fish through the water. It very severely affects the control and agility of movements.
2. Intensity of welfare impact
Some genetic modifications of fish by selective breeding can cause major welfare problems (Kolle & Hoffmann 1997). Affected fish have reduced control over their movement in the water. This would be likely to be a very serious handicap in the wild. The effects on quality of life in a captive environment are hard to assess. Research is needed in this area.
3. Duration of welfare impact
The mutant tail shape is present throughout life.
4. Number of animals affected
All fish of this breed are affected, as the undivided double fan tail is the main breed characteristic.
5. Diagnosis
The severely deformed large tail fin is obvious.
6. Genetics
The condition certainly has a genetic basis but the gene or genes involved have not been determined. We are unaware of information on the patter of inheritance.
7. How do you know if an animal is a carrier or likely to become affected?
All fish of this breed are affected, as the undivided double fan tail is the main breed characteristic.
8. Methods and prospects for elimination of the problem
The problem could be eliminated by not breeding from animals that show this trait.
For further details about this condition, please click on the following:
(these link to items down this page)
- Clinical and pathological effects
- Intensity of welfare impact
- Duration of welfare impact
- Number of animals affected
- Diagnosis
- Genetics
- How do you know if an animal is a carrier or likely to become affected?
- Methods and prospects for elimination of the problem
- Acknowledgements
- References
1. Clinical and pathological effects
Goldfish (Carassius auratus auratus) are a domesticated form of a common Chinese carp, the Chinese Crucian carp “Gibelio” (Carassius auratus gibelio) (Komiyama et al 2009). The Tosakin breed was developed over 100 years ago.
The Tosakin goldfish has a large double tail fin that is undivided – as is usually the case in goldfish with such tails – and which spreads out like a horizontal fan in a half circle. It is quite unlike the natural tail fin shape and appears to be very ineffective at powering the fish through the water. It very severely affects the control and agility of movements. Tosakin are described as being difficult to breed and rear because of their abnormal tails (http://www.allabout-aquariumfish.com/2008/08/goldfish-varieties-ryukin-and-tosakin.html).
We understand that average life span in this breed is significantly less than that of other goldfish (http://www.desktopgoldfish.com/goldfish-types.php?func=fishDetail&fish=Tosakin).
2. Intensity of welfare impact
Some genetic modifications of fish by selective breeding can cause major welfare problems (Kolle & Hoffmann 1997). Affected fish have reduced control over their movement in the water. This would be likely to be a very serious handicap in the wild. The effects on quality of life in a captive environment are hard to assess. Research is needed in this area.
3. Duration of welfare impact
The deformity is present from birth.
4. Number of animals affected
All fish of this breed are affected, as the undivided double fan tail is the main breed characteristic.
5. Diagnosis
The severely deformed large tail fin is obvious.
6. Genetics
The condition certainly has a genetic basis but the gene or genes involved have not been determined. We are unaware of information on the patter of inheritance.
7. How do you know if an animal is a carrier or likely to become affected?
All fish of this breed are affected, as the undivided double fan tail is the main breed characteristic.
8. Methods and prospects for elimination of the problem
The problem could be eliminated by not breeding from animals that show this trait.
9. Acknowledgements
UFAW is grateful to Rosie Godfrey BVetMed MRCVS and David Godfrey BVetMed FRCVS for their work in compiling this section.
10. References
Blake RW, Li J and Chan KHS (2009) Swimming in four goldfish Carassius auratus morphotypes: understanding functional design and performance employing artificially selected forms. Journal of Fish Biology 75: 591–617
Kolle P and Hoffmann R (1997) Qualzuchten bei Fischen [Excessive breeding in ornamental fish]. Deutsche Tierarztliche Wochenschrif 104: 74-75
Komiyama T, Kobayashi H, Tateno Y, Inoko H, Gojobori T and Ikeo K (2009) An evolutionary origin and selection process of goldfish. Gene 430: 5-11
The following website giving unreferreed advice about care of goldfish was accessed on 24th September 2011
http://www.allabout-aquariumfish.com/2008/04/goldfish-varieties-ranchu.html
http://www.aquaticcommunity.com/goldfish/lionhead.php
© UFAW 2012
Credit for main photo above:
http://commons.wikimedia.org/wiki/File%3ARedTosakin.png
By Lawrencekhoo (Own work) [Public domain], via Wikimedia Commons
