Do you see your cory catfish refusing to eat? Are they starving themselves for some unknown reason? In this article, we’ll go through some possible reasons why your cory catfish isn’t eating.
Why Is My Cory Catfish Not Eating? Cory catfish may arrive stressed and need time to be acclimated to your tank. They also feel more comfortable in groups. Consider sand for the substrate, add more shrimp pellets, bloodworms and change their feeding to later in the night.
If your cory catfish is not getting thinner or weaker, you should not be too worried because they could be scavenging through the night without you noticing it.
What Are Some Reasons Why Cory Catfish Don’t Eat?
There are many possibilities as to why your cory catfish are not eating. Let’s list some here and you can always leave us feedback if you have any other reasons:
- Have not acclimated to a new tank
- Affected by bullying or aggressive tankmates
- Not comfortable alone without a group of cories
- Eating through the night
- Scavenging the substrate and already full
- Eating eggs
- Disturbed by a noisy filter
- Dislike their tank conditions
- Too many plants or decorations
- Overcrowded tank
- Poor water quality
- Sick
- Bloated
- Not enjoying the type of food
- Water temperature too warm
Acclimation
Cory catfish are usually stressed or nervous when they arrive in your tank. If you have slowly acclimated them by adding tank water into the bag and allowed them to float in the bag on top of the tank for a while before putting them in, you’re doing your best to acclimate your new cory catfish.
Cory catfish might need a day or two before they are comfortable in a new tank. They can go a week or longer without food, so don’t be too concerned about it just yet.
Aggression
Some tankmates may bully or become too hyperactive around your cories which disturb their peaceful nature. Even bettas, tetras and guppies may dart around your cory catfish and cause them to retreat, hide or lay motionless without the desire to eat.
Make sure the tank has enough space and remove aggressive fish that could be fin nipping, taking their food or chasing your corydoras.
Grouping Corydoras
Cory catfish may sulk or lie motionless without partners of the same type or breed. Add more cory catfish to liven up the one who is not eating. 4 to 6 cory catfish is the minimum amount you should start with and that’s a perfect number for a 10 gallon tank. They’ll have enough room to swim and hopefully eat and scavenge the substrate for more food together.
Late Night Feedings
Cory catfish are not nocturnal, but they are active during the night. They tend to enjoy eating after everyone else in the tank is done for the day. You may notice cory catfish hunting and sifting through the substrate all night long while taking some 5-10 minute breaks for quick naps.
Try feeding your cory catfish just before you shut the lights for the night. Allow them the opportunity to feast through the night instead of forcing them to eat at the same schedule as their tankmates.
Substrate Scavenging
Your cory catfish want to find scraps in the substrate and they do so when you’re not around. You show up and they notice you, then they stop hunting. This could be common for some cories who aren’t as out-going as others. They may prefer to resume scavenging the substrate when the lights are off at night.
Corydoras prefer a smooth or sandy substrate. They can suck in the sand and expel it through their gills while ingesting the nutrients they find along the way.
Eggs
Cory catfish commonly eat their own eggs. The eggs could be unnoticed by you and before you know it, they’re consumed. The eggs are quite filling and nourishing. Once they get a taste for it, they may prefer eating the eggs more than what you’re offering.
It’s best to remove the eggs when you see them to prevent this habit from getting in the way of regular and controlled feedings.
Noises And Vibrations
Filters, speakers, or any loud sounds and vibrations could be causing your cory catfish to be stressed. They may give up eating until the racket stops. Look to replace noisy filters and prevent vibrations from affecting these sensitive fish from going on a hunger strike.
The Tank’s Aesthetics
Some cory catfish will be annoyed by too many plants or decorations that are getting in their way. They are moody at the bottom of your tank and could be giving you a sign that they want you to change up the scenery. Move things around and leave more room for their hunt to be unobstructed and more comfortable.
Water Quality
The first thing anyone usually asks you when you have a problem with your marine life is if the water parameters are correct. Perform larger water changes up to 50% weekly if you don’t think your cory catfish are eating enough.
Nitrites and ammonia levels must stay at 0 while nitrates can hover around 5-10 ppm. Poor water quality is sure to stress out your cory catfish and this could be the reason why they are not eating as much.
Sick or Bloated
Swim bladder disease or dropsy could occur if the bloated belly of your cory catfish doesn’t retreat after excretion of food waste. Try feeding them a few peas to help pass along the impacted stool. You can also allow for a fasting period of a few days to see if the bloating improves.
If your cory catifsh is not weak, sluggish, pale or showing visible skin irritation, cloudy or bulging eyes, then you shouldn’t be too concerned about any illness if the only thing you notice is that they are not eating.
Vary The Food
The food you give your cory catfish must sink to the bottom. Sometimes brine shrimp doesn’t make it down there before another fish scoops it up. Sinking pellets are harder and the shrimp varieties are beloved by most cory catfish. Bloodworms are also enjoyed. Continue to offer variety such as:
- soaked flakes
- sinking veggies wafers
- bloodworms
- daphnia
- cucumber
- peas
Water Temperature
We offer a range between 72-80°F, but try to stick to the cooler side. Warmer waters are not suitable for pepper cory catfish for example while sterbai can enjoy higher temperatures. Warmer water doesn’t contain enough oxygen and could be causing stress which leads to the refusal of food.
We hope you cory catfish resumes eating soon or maybe it’s eating at night when no one is looking. Monitor their strength and size to make sure they are aren’t getting thinner and give it time.
Thank you for reading this article and we’ll see you next time!
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