Trouble with Corys

[Satya]

I have a 29 gallon tank with a Tetra Whisper 10-30i filter and a small Hikari Bacto-surge sponge filter. I have Activ-Flora planted substrate capped with a layer of smooth pebble gravel in the tank. I make weekly water changes and add Seachem Flourish for the plants twice weekly. 
 pH 7.6

Temp 76F 

Ammonia 0ppm

Nitrite 0 ppm

Nitrate 5 ppm

kH 80ppm

gH 180ppm

I have struggled with corydoras from the start. I started with a group of 6 panda corydoras but lost all but one. Tried them again when I upgraded from 10 gallon tank to my 29 gallon tank, lost all of the new group in the 10 gallon now QT tank. I think that was a sick shipment because the pet store said they didn’t do well with anyone. Decided to try albino corydoras as I had heard they were hardier but I only have 3 left after choosing seven healthy looking friends. Last night I lost one that had been healthy in my main tank for about 2 months. Just found it dead with no warning. It’s disheartening. I tried adding driftwood a month ago (boiled it for 25 minutes and let it cool before I added it to the tank) to lower my pH in case that was the issue but I think it stressed them out. One neon tetra died shortly without warning after the add and two of my cories started to go downhill. One had a sunken belly so I shifted him to quarantine right away and he didn’t make the night. I saw another displaying odd behavior, staying at the top, bobbing for air. So I shifted it over to the quarantine and tried treating with half dose Tetra Lifeguard. He made it through the treatment and was active but died a week later (yesterday). 

I love the corydoras but it seems like we aren’t a good match and I feel horrible that I can’t make them happy. I have three happy Ottocats, a tiny curious honey gourami, one survivor panda corydora we’ve named Gloria (staying alive 2 years later from my first set of fish), four neon tetras, two nerite snails and now three albino corydoras. 

I don’t want to give up the hobby but I need some direction so that I give my fish the best life. I love growing my planted garden. And I’d love to have a stable, happy community. Should I try a different type of fish that might be better suited to my tank? Should I just stick with what I have left for a while? I feel like a fish murderer. 

[Guppysnail]

I’m so sorry for your loss.  It is a learning hobby with a harsh learning curve.  Please don’t be so hard on yourself.  Those who know a lot about fish learned it from losing a lot of fish. I can’t speak to any affect the active substrate may have with the Cory being so close to it all the time. I can tell you I have kept albino and do keep panda and Pygmy at 7.6 ph only much higher kh/gh from my tap.  I think you may be able to rule ph out as a cause. 

Edited May 7, 2022 by Guppysnail
Typo

[Blaha]

I've kept a few varieties in gravel with similar ph, so I think there is some other thing going on. I'd say the only difference for me is my water is unmeasurably hard, but Corys are hardy and should work in softer waters as far as I know. You have plenty of hiding places so I wouldn't think stress is a factor.
I guess what are you feeding them, or how much? Corys don't really eat algae and stuff like most bottom feeders. I feed mine a lot of the Xtreme Nice pellets so they can scrounge throughout the day and occasionally an algae wafer and they are a nice heathy size

[Satya]

I try to feed them a variety. For my corydoras I switch between three in the first photo, feeding them after the lights go off. About once a week I put in a slice of blanched zucchini or cucumber for the ottos and I don’t feed the corydoras that day as I see them nibble on the slice too. Every few days I will add a small piece of algae wafer for the ottos but they enjoy a pretty decent diet of algae off my plants and driftwood. For my tetras and honey gourami I switch between the three in the second feeding right after the lights turn on in the morning. 

[nabokovfan87]

On 5/7/2022 at 8:30 AM, Satya said:

I have struggled with corydoras from the start. I started with a group of 6 panda corydoras but lost all but one. Tried them again when I upgraded from 10 gallon tank to my 29 gallon tank, lost all of the new group in the 10 gallon now QT tank. I think that was a sick shipment because the pet store said they didn’t do well with anyone. Decided to try albino corydoras as I had heard they were hardier but I only have 3 left after choosing seven healthy looking friends. Last night I lost one that had been healthy in my main tank for about 2 months. Just found it dead with no warning. It’s disheartening. I tried adding driftwood a month ago (boiled it for 25 minutes and let it cool before I added it to the tank) to lower my pH in case that was the issue but I think it stressed them out. One neon tetra died shortly without warning after the add and two of my cories started to go downhill. One had a sunken belly so I shifted him to quarantine right away and he didn’t make the night. I saw another displaying odd behavior, staying at the top, bobbing for air. So I shifted it over to the quarantine and tried treating with half dose Tetra Lifeguard. He made it through the treatment and was active but died a week later (yesterday). 

I would start by dropping the temperature a bit.  How is your filter setup? Can you show us what your media setup is and if you're using cartridges or did you replace the media inside?

Flow on this filter is 125 GPH.  As an stat point, my 29G tank I run a filter with 250GPH as well as 1 air powered filter and 1 airstone.



You have a filter that may not have a ton of flow so adding an airstone as well as your sponge *might* help the fish out slightly.  I would view it like this.....

Take one of the corys and observe them.  How rapid are they breathing and how red are their gill plates?  A video of this would really help, 1-2 minutes long preferred.  I can take one of mine to compare if that helps you in any way at all.  For pandas I target 72 deg. I keep mine at 70-74 generally.  Keep in mind, that the store might have a pretty different PH compared to your tank.  This isn't a major issue and it might be a reason for some of your losses. You will get some fish that stick around and those fish will do well, especially pandas.  They are a very hearty species once they adapt to your tank, but that initial process can take some time.

Adding wood is a great way to lower the PH, so I'd recommend going that route if you feel like that is the concern for your fish and the tank.  I would also look at something like your KH/GH and anything else in the tank that would cause the PH to rise after it's in your tank.  Some rocks will affect water parameters. This is just something to keep in mind and try to sort out specifically what is causing these issues.  Until the PH is matching your water change parameters more closely, I wouldn't add any more fish.  Let the tank settle and let's talk through some issues before adding or trying to add more fish. 

Finally,

what is your water change schedule, and how much % volume of the tank are you changing when you do change water?

Do you have major differences when testing your QT 10G tank compared to your 29G display tank?

Edit: here is a video of a "similar style" of filter.  This gives you an idea of how it functions and can be modified if that is something you wish to do. 
 

 

Edited May 7, 2022 by nabokovfan87

[Torrey]

I took a workshop on identifying quality pet foods from one of the Tufts Veterinary school professors back in 2001.

I learned that prepared pet foods (class was specifically for dog foods, and professor said applies to all foods) list ingredients by weight, and the difference between "salmon" and "salmon meal" in the list of ingredients is whether the company is using the weight of raw salmon ("salmon") or is weighing after it is cooked (salmon meal).

An ingredients list with salmon at the top of the list, may not actually have a quality food, because salmon is almost 80% water. If they listed salmon meal, there's a good chance the salmon would be listed after the preservatives. 

Contrary to a lot of hype, prepared foods *do* need preservatives. If the company lists "protein meal" near the top (for omnivorous fish) and /or spirulina and other oxidative risk vegetative ingredients are included, then preservatives make the difference between a few days shelf life after opening, and 3 to 4 weeks shelf life after opening. 

Fish are only as healthy as the quality of food, the chemistry of their water, and the compatibility of their tank mates.

Cories include another parameter: health is determined by the absence of stress.

Corydoras release a toxin when they are stressed or feel threatened. This toxin will impact water quality, and it is not detected by our at home water tests. Fish, like people, have different thresholds for stress, and different triggers that can initiate a toxin release. (For more information, look at the members only video on Corydora Venom).

As Guppysnail said, until the internet, about the only way to gain much of the knowledge shared in here was trial and error. Many of us learned by failure. 

Luckily for the hobby (and for discoveries like electricity, the telephone, airplanes, and space travel), failure was simply a part of the learning process. Failing big used to be encouraged and celebrated, because it meant the individual was willing to take risks and push boundaries in the pursuit of knowledge. 

So try to give yourself at least as much compassion as you give your fish.

I recommend starting a photo or video journal, so you have hard data to look at, instead of "I added wood and think it might have stressed them", if you write down all the information including pH, GH, KH, ammonia/nitrites/nitrates, and have photographs/video when behavior changes, it will make it easier to identify "I added piece of wood, and none of my water chemistry tested different, but look at the difference in air bubbles, and foam at the surface"

See how more information can help identify potential correlations to be tested to determine if they are causation?

Thank you for trusting us with your concerns, and your desire to be a better aquarist. Try to be patient with your self. 

[nabokovfan87]

On 5/7/2022 at 8:30 AM, Satya said:

I love the corydoras but it seems like we aren’t a good match and I feel horrible that I can’t make them happy. I have three happy Ottocats, a tiny curious honey gourami, one survivor panda corydora we’ve named Gloria (staying alive 2 years later from my first set of fish), four neon tetras, two nerite snails and now three albino corydoras. 

Just doing a sanity check here.  The honey Gourami wants a temp around... 70-80 so I definitely would drop the temp down from 76-->74 and report back on how the corys themselves are breathing.

[cornelius85]

Although pandas prefers cooler water, temperature should not be an issue. I constantly keep my pandas at 77 . During summer the temps goes up to 80. They never had any problems. I bred them, raised more than 500 fries, never lost a single one. Maybe the cories you get were not healty from the start. May be there is a problem whit the place you got them.

[nabokovfan87]

On 5/7/2022 at 12:18 PM, cornelius85 said:

Although pandas prefers cooler water, temperature should not be an issue. I constantly keep my pandas at 77 . During summer the temps goes up to 80. They never had any problems. I bred them, raised more than 500 fries, never lost a single one. Maybe the cories you get were not healty from the start. May be there is a problem whit the place you got them.

It kind of depends where they come from.  If they are from a farm that is generally warmer, they might do better with warmer temps, some might do better under other conditions.  I definitely lost some when I first purchased my group.  I have had them hot, cold, and all over the place.  During the summer, it's crazy hot here and I have no real way to chill the water.

Cooler water and good flow is general what "cooler water" or river type of species prefer because there is some oxygenation differences in the water. It all can be related, it might not be.  In my experience I feel like I run higher flow and cooler tanks that other hobbyists and have success, but I also understand there is regional differences and even the same species that can be kept at a variety of temperatures successfully!

As always, it's great to have different insights to help out with the issues.

This is a good one to just enjoy, it speaks to testing parameters, temperature and the conversation at hand a bit.

 

Edited May 8, 2022 by nabokovfan87

[Satya]

As I was headed to take a short video of my corydoras behavior (who are looking active and healthy) and take photos my hang on the back filter yesterday I witnessed a tragedy. My small curious honey gourami was being sucked up against the hang on the back filter. I had been worried about the filter when we first got the honey gourami but he hadn't shown any struggles with it so I decided to leave it running but also get the sponge filter running to take over if I noticed him having a hard time. I feel horrible about this mistake. I turned off the hang on the back as my sponge filter is fit for up to 40 gallons. I turned off the lights and tried to give him a low stress day. I wasn't able to turn it around and he didn't make it. 😭

I think my next steps are to dismantle my quarantine tank and do a full clean and disinfect of all my equipment. I'm considering retiring my hang on back filter entirely. Maybe get a second small sponge filter to be able to move to my hospital tank when needed like Irene suggests. I will try reducing the temperature in the main tank and see if the cories like it a bit better. 

I really appreciate this community. Thank you for lifting up a struggling but hopeful fish keeping newbie. 

[nabokovfan87]

On 5/8/2022 at 6:45 AM, Satya said:

As I was headed to take a short video of my corydoras behavior (who are looking active and healthy) and take photos my hang on the back filter yesterday I witnessed a tragedy. My small curious honey gourami was being sucked up against the hang on the back filter. I had been worried about the filter when we first got the honey gourami but he hadn't shown any struggles with it so I decided to leave it running but also get the sponge filter running to take over if I noticed him having a hard time. I feel horrible about this mistake. I turned off the hang on the back as my sponge filter is fit for up to 40 gallons. I turned off the lights and tried to give him a low stress day. I wasn't able to turn it around and he didn't make it. 😭

I think my next steps are to dismantle my quarantine tank and do a full clean and disinfect of all my equipment. I'm considering retiring my hang on back filter entirely. Maybe get a second small sponge filter to be able to move to my hospital tank when needed like Irene suggests. I will try reducing the temperature in the main tank and see if the cories like it a bit better. 

I really appreciate this community. Thank you for lifting up a struggling but hopeful fish keeping newbie. 

Very sorry for your loss and I hope things turn around for you. I know how frustrating and down this type of an event can make you feel.  It is probably a perfect choice to run sponge filters given the flat bodied fish.  You can also ensure whatever filter you purchase for future use (if you want something with power on it) has flow adjustment.  A metal gang valve will also let you hook up multiple sponges and eventually remove them to place in another tank if need be.

There's a lot of great videos and support for issues like you've been running into.  I wish you the best of luck, future success, and continued enjoyment with your tanks.