Why Are My Corydoras Not Eating?
Use a Corydoras photo or diagnostic image that clearly relates to fish not eating.
Corydoras may stop eating because of stress, rough substrate, poor water quality, competition for food, or being kept in too small a group.
Key Takeaways
- Corydoras may stop eating because of stress, rough substrate, poor water quality, competition for food, or being kept in too small a group.
- Corydoras care basics: 20+ gallons, 22-26°C, and pH 6.5-7.5.
- Start with water testing and observation before adding medication.
What to Check for Corydoras
- Check that food reaches the bottom after lights-out or during quiet feeding.
- Inspect barbels for erosion from rough gravel.
- Test ammonia, nitrite, and nitrate.
- Confirm the group has at least 6 corydoras when possible.
Safe First Actions
- Offer sinking wafers or pellets after other fish are fed.
- Use sand or smooth substrate.
- Increase group size if the tank can support it.
- Keep the bottom area clean without over-cleaning the filter.
What Not to Do
- Do not assume corydoras can live on leftovers.
- Do not keep them on sharp substrate.
- Do not keep one corydoras alone long term.
General Causes to Consider
Poor water quality
High ammonia, nitrite, or nitrate levels can suppress appetite.
Temperature stress
Water too hot or too cold can reduce appetite.
New environment
Fish may not eat for 1-3 days after being added to a new tank.
Disease
Internal parasites, bacterial infections, or other illnesses.
Frequently Asked Questions
Do corydoras need special food?
Yes. They need sinking foods and should not be expected to survive only on leftovers.
This guide is educational and does not replace diagnosis from an aquatic veterinarian. If symptoms are severe, spreading, or affecting multiple fish, seek experienced help quickly.
Sources and Review Process
- Freshwater aquarium husbandry references for water quality, tank size, and stocking guidance.
- Species profiles and compatibility rules maintained in the TankWise data set.
- Aquarium health guidance is educational and should not replace an aquatic veterinarian for severe symptoms.
Related Species-Specific Problem Guides
A betta fish not eating is often stressed, too cold, overfed, newly added, or reacting to poor water quality. Check temperature, ammonia, nitrite, and recent changes first.
A goldfish not eating is often reacting to ammonia, nitrite, low oxygen, constipation, temperature stress, or an overstocked tank.
Otocinclus often refuse food or starve in new, very clean tanks without enough algae and biofilm. They need mature tanks and supplemental food.
Tank size, diet, temperature, and common care notes for Corydoras.
Fish not eating can be caused by stress, poor water quality, disease, temperature issues, or new tank syndrome. Check water parameters first.
Enter tank details and symptoms for a structured first-pass diagnosis.