What happened to my pygmy corys?

I have a heavily planted 29 gallon tank. There is a honey gourami, 12 neon tetras, 3 assassin snails and various pest snails. Back in February, I got a dozen pygmy corys. Initially, they seemed fine. They would swim the tank searching for food. They would sometimes school with the neons. I lost a lot of the neons within a few days of the initial purchase, but since replaced them with new ones (after a quarantine) who show no signs of bad health.
I know the pygmy corys are shy. But I'm seeing them less and less over time. Over time they started hiding more and more. At first I thought some of the shyness was because they were relatively new to the tank or because they were spooked by the deaths of the original neons. But they've been in the tank a while now. They used to come out later in the day to sift through the sand. I rarely see them when the lights are on now and even then, very few. I have a webcam with night vision. I used to look in on them in the middle of the night and would see a lot of them out and about. That's to be expected since they are nocturnal. But now I don't even see them on the webcam at night.
The last time I saw a significant amount of them was on April 8. I saw four a few days ago using my endoscopic camera. I only see two at most swimming around.
I was going to buy more in the hopes that greater numbers would make them less shy. But not knowing what's going on with them or even if most of them are still alive I'm holding off on that. At this point, I'm tempted to tear down the tank to see if they're still alive.

This is not all that surprising. I have had this species for 20 years or more. I easily spawned them (rather, they just did over several years, I provided nothing to encourage this). In a tank of their own, the original six became over 30 with fry, but I never saw them unless I sat motionless for some time. They became more out and about after they were moved into the 29g blackwater tank with Ember Tetras, Green neons, marble hatchetfish and pencilfish. But they still were skittish.

I was only able to see all of them, usually, at feeding time. I have always had a "dinner gong" system whereby I gently tap on the tank frame when I feed, always. The fish readily learn what this sound means, and the cories in all tanks will quickly come out to the spot where I drop the sinking foods. Sitting motionless, I can then count them.

Foods. Mini Bug Bites, absolutely. Alternating with Omega One Shrimp Pellets. Frozen daphnia is good, but better for full grown pygmies who can more easily eat it. Cories do not have teeth. Forget any type of worms (bloodworms), these are not natural habitat foods and with no teeth the pygmies have trouble.

Byron said:

This is not all that surprising. I have had this species for 20 years or more. I easily spawned them (rather, they just did over several years, I provided nothing to encourage this). In a tank of their own, the original six became over 30 with fry, but I never saw them unless I sat motionless for some time. They became more out and about after they were moved into the 29g blackwater tank with Ember Tetras, Green neons, marble hatchetfish and pencilfish. But they still were skittish.

I was only able to see all of them, usually, at feeding time. I have always had a "dinner gong" system whereby I gently tap on the tank frame when I feed, always. The fish readily learn what this sound means, and the cories in all tanks will quickly come out to the spot where I drop the sinking foods. Sitting motionless, I can then count them.

Foods. Mini Bug Bites, absolutely. Alternating with Omega One Shrimp Pellets. Frozen daphnia is good, but better for full grown pygmies who can more easily eat it. Cories do not have teeth. Forget any type of worms (bloodworms), these are not natural habitat foods and with no teeth the pygmies have trouble.

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I use that web cam to look in on the tank when I'm out. I can be gone for hours and still no sign of them. They used to feed during the day and now they aren't even doing that much.
I grind up the pellet foods to make it easier for them to eat. For frozen I feed daphnia, cyclops and baby brine shrimp. I do feel bloodworms once every 10 days. I run those through a food processor so that the pygmys and neon tetras can eat them.

As I typed this, literally less than a minute ago, a few came out. At least 4, but I think 5-6. They swam around almost like a panic and then went back into hiding. That's a good sign. But I'm still concerned.

Mine are the same. I had assumed I only had a few left but today I did a bigger than usual water change (bigger than my usual 80% ) and saw more than I expected from above. Mine are in a 22G long with a large herd of ember terta. I have a similar concern, do I buy more to increase the group, is something in the tank causing them to die off, or are they just very shy?

Hello. 29 gallons is small and doesn't allow much room for a mistake in the management of the water. When you think about it, water makes up most of everything that makes up a fish tank, so it's just common sense to concentrate your efforts on the water. If you change enough water, you don't need to be bothered with much else. Review your water change routine. You may find that your fish are more active and more visible in near pure water conditions.

10 Tanks (Now 11)

Mine are the opposite!
I have them in a planted 20 gallon with my habrosus cories. They all forage around together and are always out and about no matter what time of day. And never worry when I come near, might stop and see if I'm going to feed them, and then ignore me.
I had them in my 47 gallon community tank previously, and would hardly see them. Forever trying to catch sight of them to count them. So stressful!
I've found them to be very cluey. When I was trying to transfer them to new tank, after I caught one with the net the others knew what I was up to and vanished. For hours. They remembered for days, and I was very slow and careful with the net. No chasing them around the tank. Smart little things.
Is your honey peaceful? Could it be harassing them?

seangee said:

Mine are the same. I had assumed I only had a few left but today I did a bigger than usual water change (bigger than my usual 80% ) and saw more than I expected from above. Mine are in a 22G long with a large herd of ember terta. I have a similar concern, do I buy more to increase the group, is something in the tank causing them to die off, or are they just very shy?

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I might try a larger water change and see what happens. Now that I've seen a few of them, I'm also going to add more and see if that helps.

10 Tanks said:

Hello. 29 gallons is small and doesn't allow much room for a mistake in the management of the water. When you think about it, water makes up most of everything that makes up a fish tank, so it's just common sense to concentrate your efforts on the water. If you change enough water, you don't need to be bothered with much else. Review your water change routine. You may find that your fish are more active and more visible in near pure water conditions.

10 Tanks (Now 11)

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My tank is heavily planted including fast growing floating plants (salvinia minima and elodea). I do a 50% water change every week, I may increase that amount or do a supplemental change at a different time in the week.

Fray said:

Mine are the opposite!
I have them in a planted 20 gallon with my habrosus cories. They all forage around together and are always out and about no matter what time of day. And never worry when I come near, might stop and see if I'm going to feed them, and then ignore me.
I had them in my 47 gallon community tank previously, and would hardly see them. Forever trying to catch sight of them to count them. So stressful!
I've found them to be very cluey. When I was trying to transfer them to new tank, after I caught one with the net the others knew what I was up to and vanished. For hours. They remembered for days, and I was very slow and careful with the net. No chasing them around the tank. Smart little things.
Is your honey peaceful? Could it be harassing them?

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The honey is very mild mannered. I've never seen any aggressive behavior from him. He has the back upper left corner of the tank he seems to have claimed but none of the other fish go there. The other fish prefer the mid to lower portions of the tank I've never seen him chase another fishw away from there (or anywhere else). Even when the honey swims in the rest of the tank, he never does anything to the others. I remember one time he was eating peacefully alongside the pygmys when he decided that he would like some of their food. They didn't seem to mind him and he didn't do anything to them.
I never see any problems with the neons either. Sometimes one or two of the pygmys would swim with the neons, That happened today when they made their appearance. The neons don't seem to mind them at all.
I wonder if your habosus are acting as a dither fish for the pygmys. Even if that is the case, I don't want to add anything more than a few more pygmys to my tank. The water quality is good and everyone has plenty of space. I'd prefer to keep it that way.

Fray said:

Mine are the opposite!
I have them in a planted 20 gallon with my habrosus cories. They all forage around together and are always out and about no matter what time of day. And never worry when I come near, might stop and see if I'm going to feed them, and then ignore me.

Click to expand...

I have the same experience with my 10 gallon and green emerald cory (5). They are in there with 3 zebra danios. I had fake plants but have since transitioned most to live plants. The plants aren't so many or so large that it allows the fish to hide much at the bottom, so it's pretty easy to see the cory.

I’ve ten Pygmy’s and ten Heterandria Formosa in a 120L atm. It’s well planted so gets a 70%ish WC every weekend as there’s not a lot of it gravel vaccable.
The Pygmy’s are most visible immediately after the WC but that only lasts a few hours then it’s back to only one or two being in the open with one or two visible resting on leaves, branches or rocks in the background.
The HFS always have half a dozen representatives visible.
I’ll be buying a few more Pygmy’s soon. Then possibly Ember Tetras and Scarlet Badis to add a bit of colour.
What I do like now that I’ve no larger fish is the smaller number of fish and that occasionally on approaching the tank there’s no fish visible at all.
The four large Amanos are now more prominent. Unfortunately RCS can’t be added atm due to the prominence of the HFs % wise. When I had Endlers, Medaka and WCMMs in the tank the HFs left them alone but as soon as the WCMMs were added to the patio pond the last RCS were toast. Does anyone know if adding more smaller fish like Embers, Scarlet Badis, Pygmy’s would allow RCS to live safely? They were in there for a year alongside the HFS and bigger fish quite safely.

I just added some more pygmys to the tank. One thing I noticed about these new guys while I kept them in quarantine. They seemed pretty bold for pygmy corys. I put plastic pipe fittings and plastic plants in the quarantine tank for them to hide in or behind, but they rarely did. They were out and about. The quarantine tank was also right by my video gaming chair so they got used to my presence pretty well. They didn't scurry when I approached the tank.
So after the quarantine period, I added them to the main tank. I figured one of two things was going to happen. Either the new pygmys would embolden the originals to come out more. Or they new pygmys would join the originals in hiding. It's a little of each. The new pygmys are still generally out an about. I see them all the time during the day. And they do seem to have a positive influence on the originals. Sometimes a few of the originals will join them during the day. When I watch them at night on the webcam, it's a big old pygmy cory party then.
They're still new but I think these are good signs. Hopefully, I'll see more of my corys moving forward.

I bought six more little ups at the weekend. I’ll be adding them to the main tank in a couple of weeks time. Hopefully that’ll help the others get out n about a bit more

Since I've added some, they've been coming out more. I wasn't at home for this. I was looking in on my tank with my webcam. Those pygmys were having a party when I wasn't there.