Is it normal for Corydoras to swim to the surface of the tank?

As the proud owner of cory catfish, you probably spend a fair amount of time watching your pets and, as such, will notice some particular patterns and behaviours.   While most of these behaviours are perfectly normal, there are a few you may want to keep an eye on and, we’ll take a look at some of these in this article. 

Why do cory catfish swim to the top of the tank ?

If you’ve noticed your fish doing this, relax – it’s absolutely normal and, you cory will do this for two reasons: 

Feeding – Your cory catfish may have spotted a tasty morsel floating on the surface of the water and, so, will swim to the top of the tank to retrieve it. 

Oxygen – Although the water in your tank is oxygenated (and you can ensure that it is by installing a good quality bubbler), your corydora may occasionally make its way to the top of the tank to grab a gulp of air.  

Swimming to the surface for food and air is absolutely routine behaviour for your catfish and nothing to worry about.

Cory behaviour red flags

Just like us, your cory catfish can suffer from stress and, the following are some warning signs to look out for: 

  • Frantically swimming around the tank
  • Erratic and odd swimming patterns such as swimming upside time
  • Lethargic movement
  • Refusal to eat
  • Frequently gasping for air at the surface of the tank
  • Change in colour, particularly turning white
  • Discoloured gills

One or more of the above may indicate a problem with the water in your tank which should always be kept clean and oxygenated.  You should also make sure that you line your tank with soft, natural sand and place some driftwood and dense vegetation on the floor of the tank to provide some hidey spaces for your cory catfish during daylight hours. 


In most cases, there’s no need to panic if your cory have a habit of rising to the surface of the tank, however, if you spot any of the red flag behaviours listed above, you may want to seek advice from a specialist.