Dye and Die

In today’s hobby a debate is never too far away among experienced aquarists. A subject that is repeatedly debated is dyed fish, albeit that it is not really a debate but more often an all round condemnation of the practice. I will outline to you what the process involves and let you make up your own mind.

What are dyed fish?

Dyed fish are aquarium fish that have been unnaturally dyed with an artificial colour to make them look more appealing to the buyer. Commonly they include Corydoras, Glassfish, Parrotfish, Tetras, Gouramis and some other large cichlids. In Ireland the most commonly available are Dyed Parrotfish, Glassfish and Tetras.

Dyed Parrotfish.

How are they dyed?

The process of dyeing the fish is vastly contested however there are 3 common practices known in the hobby:

  1. Injection of dyes using a syringe/hypodermic needle.

  2. Tattooing of the fish using a laser.

  3. Dipping of fish in a dyed solution.

N.B Fish can be fed colour enhancing food and can also be genetically modified to produce new colour strains however that subject will be covered in a future article.

Tattooed Parrotfish.

Why are many aquarists against the practice?

This practice is condemned by many in the hobby as it is felt that it is unnecessary, cruel, leads the fish prone to illness and infection and the high mortality rate due to the method of dyeing.

Dyed Corydoras

Illnesses associated to dyed fish:

Being dyed is a stressful and painful process for the fish. Depending on the process used it can lead to open wounds being left on the body of the fish. Dirty needles being used on multiple fish considerably adds to the risk of disease or infection. These diseases are known to spread quicker and easier in an already weakened fish.

Mortality of dyed fish:

The mortality rate of dyed fish is another contested issue. I will not type any random high percentage figure but I will say that the process itself undoubtedly kills many fish and the associated illness from the process would lead us to believe that the mortality rate is high.

The Injection Method

This article is focussed mainly on the injection method as this is the most common dyeing process.

Disco Fish first entered the hobby in the 1980’s. The fish keeping public were unaware how a glassfish (Parambassis ranga) could have so many different colours. It was apparent that they had been artificially coloured.

Dr Stan MacMahon and Dr Peter Burgess set about finding out. They sedated some glassfish and examined the areas where the dye had been applied. Under a microscope they found that the dye was not merely painted on the outside of the fish but it was under the epidermis. Given the location of the dyes and the patterns involved it lead them to believe that the fish must have been injected a number of times to achieve the end result. Considering the relative size of an epidermic needle to such a small fish and coupled with the increasing scientific evidence that fish can indeed feel pain it must be a terrible experience for the fish.

Who is dyeing the fish and why?

The fish are generally imported from large fish farms in Southeast Asia. They are still widely available. They are dyed purely because of supply and demand. There is clearly a market for them as shops knowingly/unknowingly buy them in and sell them on for high prices all over the world.

What can we do about this practice?

Simply do not buy dyed fish. If you are in a shop that sells them, approach the manager and ask them not to stock them. Refuse to give the shop any of your business until they stop selling dyed fish.

Name and shame them, word of mouth is a strong thing. Let people know who is stocking dyed fish. Shame them into not selling them.

Awareness is the key, we must educate fish keepers (new and experienced) and do what we can to stifle the demand for these fish.

Just say NO to Dyed Fish.

Peter O’Brien

January 2007.