Why it's cruel to dye
Dr Stan MacMahon and Dr Peter Burgess explain the damage done to fish when they are barbarically injected with dye.
Copyright © Practical Fishkeeping
Some fishkeepers, and possibly even a few traders, may be puzzled as to why so much fuss has been made about dyed fish.
On the face of it, the practice of dyeing or "painting" the fish seems fairly innocuous and the artificially dyed specimens are certainly very eye-catching in their various "day-glo" colours.
So why push for a voluntary ban on selling them? Our investigations have revealed the truth behind the dyed fish saga.
Disco fish
Our first encounter with dyed fish was back in the late 1980's.Thousands of artificially coloured glassfish, Parambassis ranga (formerly Chanda ranga) were imported into the UK.
The glassfish, so named because of its naturally semi-transparent body, obviously makes it an ideal subject for "painting".
They were seen with fluorescent shades of either blue, purple, red, yellow, orange or green produced by dyes.
They were (and still are) imported under the names "painted glassfish" or "disco fish"(presumably because their almost fluorescent colours resemble discotheque lights).
How is the dye applied?
Intrigued as to how the dye was applied we decided to carry out a little research.A few coloured glassfish were sedated in MS222 anaesthetic and observed under a binocular microscope. It became apparent that the dye is not on the surface of the fish, but lay under the epidermis.
Furthermore, the dye appeared fluid and could be moved slightly by gently squeezing the coloured area.
This suggested that it must have been injected into the fish at various sites over the body in order to form the distinctive colour patterns.
Our fears were confirmed a few years later when we were shown photographs of the colouring process, revealing that each fish is individually injected using a syringe and needle.
The practice of dye injection is undertaken by fish farmers in some regions of Asia (but not Singapore as far as we know).
Clearly, the common name "painted glassfish" is a cruelly misleading description.
If one considers the relative bore size of the injection needle with that of a glassfish, it would be the equivalent of us receiving several jabs using a needle of pencil-sized diameter - not a pleasant thought.
As experienced fish scientists, we would never dream of injecting fish of such small size. No wonder the injection process is alleged to cause high mortalities.
Increasing the risk of disease...
A survey which we carried out in the south of England revealed that over 40% of painted glassfish appeared to be suffering from lymphocystis virus.This disease manifests itself as a small whitish growths on the fish's body and fins.
An examination of the white growths under the powerful electron microscope confirmed our diagnosis. In contrast, less than 10% of the natural (unpainted) glassfish had lymphocystis.
It is possible that the injection process increases the risk of this disease, perhaps by transmitting the virus from fish to fish via the needle (the same needle is used to inject tens or even hundreds of fish).
Alternatively, the stress of being injected with the dye may lower the fish's natural immunity to lymphocystis.
It must be said that, in our experience, those glassfish which survive the injection process go on to live fairly normal lives, despite the gaudy dyes present within their bodies. In time, the dye fades.
Moral issue
Many people believe that fish do not feel pain and so injecting them with dyes is perfectly acceptable.In fact, increasing scientific evidence suggests that fish are indeed capable of feeling pain, though we have no way of telling whether they perceive painful events in the same way as we do.
So dye injection is likely to be a painful experience for the poor glassfish.
In fairness, many traders and hobbyists were mislead, just as we first were, into thinking that these fish were simply painted with the dye. Now that the truth is out, it's time to stop this cruel practice, once and for all.
Other species which are sometimes dyed
Glassfish are not the only species which are subjected to artificial colouring.Many types of albino fish also make ideal "white canvasses" for colouring. We have observed the following artificially coloured fish in the UK, and suspect there may be others.
Albino versions of Corydoras catfish, such as aeneus; Tiger barbs; Albino Epalzeorhynchus (formerly Labeo) such as the Red-finned shark; Black widow tetras; Rams and some Botia species.
Typically these exhibit red or blue on part of the body, but the dyes are not as bright or gaudy as those used to inject glassfish.
Fish which have pale or semi-transparent bodies such as the glassfish, Kryptoterus, also suffer.
Other fish on offer
One supplier in Thailand currently offers a very wide range of dyed fish on its online stock list which are clearly marked as being injected. Their stocklist is shown below.Color Silver Shark
Color Albino Rainbow Shark
Color Albino Irridescent Shark
Mixcolor Ompok
Red Ompok
Blue Ompok
Green Ompok
Yellow Ompok
Orange Ompok
Purple Ompok
Pink Ompok
Tinfoil Blushing-blue
Tinfoil Blushing-red
Tinfoil Blushing-green
Tinfoil Blushing-pink
Tinfoil Blushing-purple
Tinfoil Assorted Color
Color Tiger Barb
Color Redtail Botia
Blue Redtail Botia
Red Redtail Botia
Green Redtail Botia
Yellow Redtail Botia
Orange Redtail Botia
Purple Redtail Botia
Pink Redtail Botia
Two Color Glass Fish
Red Glass Fish
Blue Glass Fish
Green Glass Fish
Yellow Glass Fish
Orange Glass Fish
Purple Glass Fish
Pink Glass Fish
Black Color Glass Fish
Color Tetra
Red Tetra
Blue Tetra
Green Tetra
Yellow Tetra
Orange Tetra
Purple Tetra
Pink Tetra
Black Tetra
White Tetra
Others...
The PFK Ban Dyed Fish Campaign
Practical Fishkeeping ran an award-winning campaign which started in 1996 and asked aquatic retailers to sign a pledge that they would not sell dyed fish.The majority of British retailers signed up and dyed fish are now relatively uncommon in the UK.
Further reading
Clarke, Matt (2006) - Pink danios: dyed or genetically modified?, Practical Fishkeeping blog. Mon June 19, 2006.
Clarke, Matt (2006) - Magazine publishes guide to cosmetic fish surgery, Practical Fishkeeping website news. Mon June 12, 2006.
Clarke, Matt (2006) - Time to email your MP?, Practical Fishkeeping blog. Thu March 16, 2006.
Clarke, Matt (2006) - It wouldn't happen to a kitten, Practical Fishkeeping blog. Wed February 22, 2006.
Clarke, Matt (2006) - Company offers custom fish tattoos with laser, Practical Fishkeeping website news. Thu February 23, 2006.
Clarke, Matt (2006) - Dyed fish to remain legal, Practical Fishkeeping website news. Fri February 17, 2006.
Clarke, Matt (2005) - New dyed tropical fish on sale, Practical Fishkeeping website news. Thu December 15, 2005.
Clarke, Matt (2005) - Are dyed fish here to stay?, Practical Fishkeeping blog. Mon October 24, 2005.
Clarke, Matt (2005) - Fashions in fish sales, Pet Product Marketing/Practical Fishkeeping website. January 18, 2005.
Clarke, Matt (2005) - Dyed fish campaign hits halfway mark, Practical Fishkeeping website news. Fri July 22, 2005.
Clarke, Matt (2004) - Join the global fight against dyed fish, Practical Fishkeeping website news. Fri December 17, 2004.
Clarke, Matt (2004) - Practical Fishkeeping relaunches Dyed Fish Campaign, Practical Fishkeeping website news. January 23, 2004.
This article was first published in the March 1998 issue of Practical Fishkeeping.
Dr Stan MacMahon and Dr Peter Burgess 1138 (words, 4516 hits)Published online: 02.14.03
Reader comment
Date: Thursday March 27th, 2008, 1:04 am
"yeah it is disgustng!!
i was on ebay the other day and was shocked 2 see some1 selling dyed ghost fish it said u could have them pink,green,blue ect so i no 4 sure they were dyed n there was a photo.
i think they look better as they were in there natural beauty they dont need 2 b dyed it spoils the look."
Date: Thursday March 27th, 2008, 1:04 am
Reader comment
Date: Thursday July 17th, 2008, 6:40 pm
"What about the tattooed fish? I understand they use a laser beam to etch patterns into the fish. I found some with a heart on the site at my local shop and was very disappointed to see that.
Is this process also cruel?"
Date: Thursday July 17th, 2008, 6:40 pm
Reader comment
Date: Wednesday September 3rd, 2008, 12:57 am
"I wish they were banned here in the US, the land where profit drives everything. Along with those GloFish...they should all be banned, but apparently ignorant people still buy them simply because they look "cool"."
Posted by: Alonso Garcia - 3 months, 2 weeks agoDate: Wednesday September 3rd, 2008, 12:57 am
Reader comment
Date: Monday October 27th, 2008, 1:32 pm
"i totaly agree that fish shouldn't be treated this way and we should let the fish beautiful in their own way"
Posted by: Victoria Langthorp - 1 month, 2 weeks agoDate: Monday October 27th, 2008, 1:32 pm
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"having read your article on line I am disgusted that this practice is allowed to continue. I would urge all fish keepers to stop buying any fish they suspect of being dyed."
Posted by: Dennis Laws - 1 year, 7 months agoDate: Friday May 11th, 2007, 2:34 pm