The Golden Loach the Myths & Mayhem

This beautifully coloured little fish is a fairly common fish to be seen in the aquarium trade in the UK. It is sold for both cold water and tropical aquariums. There are many pages and articles that are misleading or just don’t go into enough detail for this fish and after a bit of feedback on my Instagram page I thought I would write an article on this often miss understood fish. An article by Practical Fish Keeper even went as far as naming this fish as one of the worst community fish of all time. I would like to argue this point that they are not and have a place in fish keeping. I have used them in many of the aquariums I look after and I have rarely had any problems with them.

For starters the name 'loach' is a bit misleading as common names most often are. These are not a Botia species like the Yo-yo or striped loaches so don’t expect similar behaviour from these. Its Latin name is Gyrinocheilus aymonieri. An Asian species that is tolerant of a wide range of pH and temperature. They are said to be aggressive and are sold for both cold and tropical aquariums. I have only seen them become aggressive in cold water aquariums when the slower growth of algae isn't enough to feed them, so they then start sucking to the sides of slow moving goldfish. This damages the goldfish and can eventually kill them. This is where the reputation of their aggressive behaviour stems from. They are brilliant algae eaters in tropical aquariums. They are territorial to their own species and they will push out the weaker of their kin away from the feeding spots. These weaker fish slowly lose weight or stay small and should be re-homed if they start to look emaciated. They are also very active and throw themselves around the aquarium taking little notice of anything else. If anything does die they will clear up and quickly, this behaviour again adds to their aggressive reputation. I have almost daily contact with these fish and these little guys will keep your tank clean for years. I have had them live in aquariums for up to 5 years.

However I must add some more detail to my experiences. Most of these Golden Loach I have had direct experience with over many years did not grow larger than 10cm. I have had 2 that have grown much larger, in fact one was 25cm in length! A monster I kid you not, both were kept in cold water aquariums. Both had to be removed because they had become aggressive. The vast majority are kept in aquariums of 200L or larger, most in tropical planted aquariums and never with goldfish. In a 400L tropical planted aquarium I would add 3 and expect to remove one after a year once the other 2 had grown bigger and started pushing the small one off the algae. I believe that the dense plant growth and abundance of leaves and algae to eat prevents them from becoming a problem. I have also noticed that they are the first to suffer or die if the aquarium becomes low in oxygen, perhaps in tropical aquariums their growth is restricted by the warmer water which naturally holds less oxygen? I had firmly believed this oxygen restriction but after a discussion on Instagram it appears that they can grow large in tropical water too and also become a problem.

Conclusion? Well in this case I think you could argue either way for their use. I will continue to use them but I do have the luxury of having many aquariums under my care and if any fish becomes a problem it is easy for me to re-home them. I think that we would all agree that they are not suitable for nano aquariums or cold water aquariums with slow moving fish. Perhaps I should just say they are suitable for community aquariums but with caution.


Check out this book on loaches it may be of interest. Available from Amazon UK.


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