You are here:

Fish/Gene modification in pet fishes


i have been seeing fishes coming in various forms like black moore with their eyes protruded and lion head or some golds with a an orange hat on their head ,are they really natural fishes or syntesized by genetic engineering??
 At what level is the gene modification works are performed in the pet fishes?I'm can explain me even in complex terms i'd understand or somehow i'll do .

This is an excellent question. I appreciate your curiosity and critical thinking!

This topic is what gave me my understanding of genetic engineering and selective breeding. It turn out that they are the same. This applies to fish, dogs, food (such as crops and the heated GMO debates), pretty much everything people have domesticated.

When people domesticate something, there are certain traits they like about it. Goldfish look like this naturally:
This is article is on the same topic.

The point is, when people started keeping goldfish, they liked the gold color for example. So they breed the individual fish that had the best traits according to what people liked. This became long fins, strange protruding eyes, and other characteristics that look like deformities to me. The fish can't don't develop these traits because the ones that look natural are the best fit to survive and reproduce in accordance to the theory of evolution. In a captive environment like an aquarium, we can choose to breed individuals with unusual or beautiful traits because we take care of them. In a captive setting, we breed goldfish for their ornamental qualities rather than their survival and reproductive qualities because we take care of that for them. Wild fish have to survive and reproduce, whereas captive goldfish just have to look nice.

This is genetic engineering. This is selective breeding. They are the same, but many people are opposed to the practice for whatever reason, so they call it genetic engineering because that sounds scary and unnatural and therefore bad to many people.

An easier example to follow is the dog or chicken. When these were domesticated, people found them useful. People breed the individuals with desirable traits until those traits became standard in a group, like they are in varieties of dogs or chickens.

These traits would not become apparent in nature. This is like I said with the goldfish, the natural traits are those which the species has developed to best ensure reproductive success in its natural environment. Black moors would not become dominant in the wild. If they weren't eaten due to their slowness or lack of coordination, they would be outcompeted by their natural counterparts, and would fail to reproduce on the same level if at all, making the protruded eyes trait rare or nonexistent in future generations.

The same happens with food. People like food that produces high yields with the minimum resource input, so we selectively breed specimens to have these traits. That's all there is to it. That is "genetic engineering".

In my opinion, there is nothing wrong with any of this. I personally think that there are no downsides or dangers to genetic engineering through selective breeding. The things we can achieve and learn through selective breeding are truly remarkable and have already changed virtually every aspect of our lives. Selective breeding of plants and animals is what allowed people to settle in cities rather than live as hunter/gatherers. Selective breeding such as that demonstrated by the "fancy" goldfish made human civilization the way it is today.

With the help of modern lab. based science, we can target specific genes and make the selective breeding process even more efficient and effective.

I understand this is a difficult and controversial topic. I hope that this very basic explanation will help you in your understanding of goldfish. :)
Also, everyone is entitled to their own opinion on the matter. Though I personally think selectively breed goldfish are repulsive, the practice and some of the science that goes in and comes out is incredible and applicable to everyday life.

Once again, my apologies if this offends you in any way or you happen to disagree with me.

Keep thinking of good questions like this!


All Answers

Answers by Expert:

Ask Experts




I can answer questions relating to the scientific aspect of the hobby (fish ecology, biology, genetics, etc. ), aquacultural and breeding aspects, and have experience with nearly all "brackish" fish in the trade. I also have lots of experience breeding fish, like angelfish, tetras, cichlids, and various livebearers. I also have lots of experience with many freshwater fish, especially "monster" fish, like stingrays, arowana and Saratoga, cichlids, catfish, etc. Please ask questions about anything except for true saltwater (reef) tanks.


Too much to fully list, but I will never have never enough to satisfy myself.

River Watch of Colorado Monster Fish Keepers USA Canoe/Kayak

Student, but I've been involved in many projects involving aquaculture and fish biology. I'm currently helping design a massive stream improvement project on the St. Vrain river. I am studying fisheries ecology, techniques, hatcheries, and management practices for north american freshwater systems.

©2017 All rights reserved.

[an error occurred while processing this directive]