Why is my Cory catfish turning white?

The cory catfish, or as it is commonly known, the corydora, is usually black white or brown in colour with dark spots or orange stripes.  This easy to care for tropical fish is a joy to watch and will usually stay healthy and live for up to five years with relatively little maintenance.  If you’re a new cory catfish owner, you’ll understandably be keen to do everything you can to keep your pet healthy and, one thing to look out for is a change in the fish’s appearance, particularly in its colour. 

Why is my cory catfish turning white?

Cory catfish becoming paler or turning white is quite a common problem and, this can be down to a few things, including: 

Stress – like us humans, corydoras can suffer from stress due to a change of environment or habitat – for example, inadequate tank provisions such as not enough room, not enough sand or unclean water.  It’s important to make sure that your tank replicates the fish’s natural habitat as closely as possible in order to keep your cory healthy. 

Illness – Sadly, a change in colour may indicate that your fish is ill – you should immediately check the water and tank conditions to identify any changes and rectify if possible.  Otherwise, make a list of symptoms and discuss these with a professional.

Environment adjustment – In some cases, a cory catfish will turn white when first placed into your tank.  This is usually nothing to worry about and the fish will most likely darken in colour again once it is acclimatised to its new environment.

Diet – It’s quite common for the cory to turn white or change colour if its diet has changed.  Make sure that you’re feeding your fish on a varied diet which should include bloodworms, shrimp pellets and catfish pellets. 


A physical change is always a worry but, the good news is that, in many cases, the solution will be as simple as checking the conditions of your tank and adjusting accordingly.  If, however, this doesn’t work, it’s a good idea to seek advice from a vet or fish specialist.