School of Pygmy Corys all hiding in the back on the floor

Hi everyone. I have about 25-30 Pygmy Corys. For the first few months after I purchased them, they would school and swim all over the tank. It was really beautiful. Now they all hide in the back behind some driftwood in the back of the tank sitting peacefully on the floor.

I think they might be nocturnal? So they are just sleeping during the day? They have zero signs of stress or disease and I have yet to find any dead bodies. They seem completely happy back there. Sometimes I worry that they are dead or sick and I put my hand back there and they, as a school, move away from my hand. Then move back to their favorite spot and all of them sit on the floor again.

Just wondering if any experienced Pygmy Cory keepers see this type of behavior.

Oh yes, and I do see a couple of pairs during the day displaying mating behavior and sometimes a small group of 5 or 6 would forage a bit and then head back to the "settlement" in the back. haha.

No emergency as they all look healthy just wondering about the behavior.

 

What are your parameters? Do you have any large fish that might be picking on them?

 

Could you place a tank-pic ?

 

Crimson_687 Hi there! Water parameters are good, PH about 7.8, no ammonia, or nitrites, a tiny bit of nitrate. But I'm liquid dosing for plants. I am doing a double dose of Excel due to BBA and potentially Staghorn. The plants have exploded though, I need to cut them back a bit. Temp stays about 76 as I have a thermostat on it connected to a heater and some fans just over the water for cooling.

As far as big fish? the only "big fish" I have is 6 Golden White Cloud Minnows, 2 Super Red Longfin Bristlenose Plecos, and 5 Otos. They all completely ignore the pygmy cories. I also forgot to mention this is a 100g tank that has a thriving colony of Blue Velvet/Dream Neocaridina shrimp.

My daughter observed that they do come out and explore a bit more when the lights are out, but I do miss them schooling the way they used to!

DoubleDutch I've attached a pic!




The two hanging breeder tanks are for my Shrimp, as I was very suspicious of the Minnows and especially the Scuds in the tank eating the shrimplets. Uggggg... I hate Scuds but I can't get rid of them without doing something bad to my shrimp colony. Oh well. Anyway, the breeders are working well, I have a ton of shrimplets in them!

So... any thoughts on the Pygmies? As I said, they are quite healthy, and I watched a few pairs going around the plants breeding too! Even saw, what I think, was the female pop a pretty big egg out of her as she rubbed herself on the plants. The active breeders are the only ones swimming around during the day. The rest of them are hiding behind the big driftwood on the right side of the tank.

I'd get a pic of them sitting on the floor but they just run away from me as soon as I go near them. Are they just really really shy? I will say they have been this way for a long time now and I'd thought I'd just ask everyone here what their thoughts are on this. Why would they develop this after about a month of schooling? Very strange.

 

I see no on every replied to this and I have the same problem. I have a school of pygmy corys and a school of ember tetras. They used to all school together (I think the embers were just curious about what the pygmy corys were up too.) After about two weeks I noticed some of the tetras started foraging with the pygmy corys. As in picking around in the gravel for fallen food. I have 2 bowls (kind of an interpretation on an ikebana style) and they spend 100% of their time behind the bowls. I don't know if they come out at night or not. I literally have not seen a single one in 3 days. They started staying hidden most of the time after a thorough cleaning. Maybe they just hate me now - though the embers seem unfazed. Water Parameters: Ammonia 0, Nitrites, 0, nitrates 5, PH 7.8. I guess I'm just bummed because the first few days they turned the air-stone into an underwater slip-n-slide and seemed to be having fun. Could it be that the Embers are picking on them and I haven't seen it?

Also, when I saw 4 of them 3 days ago, they seemed full and healthy so I don't think they are starving. But haven't seen one since before Thanksgiving.

 

I had an interesting situation. When i had kribs all 15 of my pygmy would hang out in the front corner next to the kribs - why because the kribs kept all the other fishes out of their territory so they felt super safe there in the open. After i removed the kribs they still stayed there out of habit but every time i walked into the room the scattered. Eventually they just stopped staying there and now they hang out in the back (which is densely planted) (see picture). My guess is they just didn't feel safe in front any longer so now they hang out in the back...

My guess it is the same for your pygmy - they just don't feel comfortable in front any longer.

 

This happened to me with my pygmy corys aswell. I found the solution. I started with 11 and they were very active. 3 of them had come in without barbels so had some kind of infection and as it got worse it was clear they were sick. Inactive and sat in the spot where most of them used to hang out and eat at the fron of the tank. All my other corys started hiding at the back and even other fish like an oto wouldn't come out anymore. Moved the sick ones to qt and the same day all the healthy ones came right back out.

 

I have never had pygmy corydoras but I have had a similar situation with my otos, at first they were always out and about, and I just had apistos apart from them. When I got neon tetras and pencilfish the otos became nocturnal and I hardly ever saw them. Recently I have removed the neons and pencilfish and although I now have some quite big Cichlasomas in there they have started to appear again. Strange.

 

I have never had pygmy corydoras but I have had a similar situation with my otos, at first they were always out and about, and I just had apistos apart from them. When I got neon tetras and pencilfish the otos became nocturnal and I hardly ever saw them. Recently I have removed the neons and pencilfish and although I now have some quite big Cichlasomas in there they have started to appear again. Strange.

My Otos are starting to hide from my pencilfish as well I don't think it is unusual as the pencilfish are actually pretty aggressive. They're too small to actually hurt anything but Otos are timid

OP I would have to agree with the others on this one, it likely is just an issue of feeling safe out in the open. Your tank looks like an ideal environment for them so unless you see signs of disease or they aren't eating I wouldn't worry too much. You can try rearranging your scape, sometimes that can help

 

Interesting...the Cichlasomas and even the apistos are much more aggressive than the pencilfish, though, not to the otos though. But probably the pencils dash around a bit more, maybe that is what they don’t like??

 

Interesting...the Cichlasomas and even the apistos are much more aggressive than the pencilfish, though, not to the otos though. But probably the pencils dash around a bit more, maybe that is what they don’t like??

It probably boils down to individual temperament, my pencilfish can be pretty aggressive haha. I have 4 male though so there's that

 

Maybe as an experiment, I'll move the tetras to the hospital tank for a few days and see what happens. I bet chasing ember tetras with a net won't further stress the corys at all . . . . I can't imagine having a tank with fish that will live another 3 plus years and never see them.

 

Just a quick update on my tank. My pigmies are all still hiding at the back of the tank and I suspected that they went nocturnal on me. So I camped out in the dark with them till my eyes adjusted and had a very low red light way in the back of the room so I could make them out, and yes the pigmy's were out and foraging. During the day they are on alert and when they see me walking into my office (where my tank is) they slowly move to the opposite side of where I am. It used to bother me but not so much anymore. As long as they are healthy I'm happy.

I honestly think they are very impressionable. Like if one of them is really skittish, then it infects the rest of them with the same sort of behavior. As an example, I recently introduced 4 green corys into the tank, and they are always busy foraging. When they come near the resting pygmies, they all start going tail up foraging too! It's kind of funny. It doesn't always happen but it happens enough to notice it.

I also have about 40 ember tetras in the tank as well that school 99% of the time. I was hoping that they would serve as a dither fish and encourage the pigmies to come out and school as well. It happened for a little while and then they pygmies when nocturnal again.

Anyway, sorry that others are experiencing the same disappointment with the daylight behavior but I hope they are all healthy and none the less!

 

I could put them back in front if i reintroduce the kribs (I think) but then the kribs would cause other problems. Anyway i only feed the fishes in front and when they get hungry enough they will come out earlier

 

Just a quick update on my tank. My pigmies are all still hiding at the back of the tank and I suspected that they went nocturnal on me. So I camped out in the dark with them till my eyes adjusted and had a very low red light way in the back of the room so I could make them out, and yes the pigmy's were out and foraging. During the day they are on alert and when they see me walking into my office (where my tank is) they slowly move to the opposite side of where I am. It used to bother me but not so much anymore. As long as they are healthy I'm happy.

I honestly think they are very impressionable. Like if one of them is really skittish, then it infects the rest of them with the same sort of behavior. As an example, I recently introduced 4 green corys into the tank, and they are always busy foraging. When they come near the resting pygmies, they all start going tail up foraging too! It's kind of funny. It doesn't always happen but it happens enough to notice it.

I also have about 40 ember tetras in the tank as well that school 99% of the time. I was hoping that they would serve as a dither fish and encourage the pigmies to come out and school as well. It happened for a little while and then they pygmies when nocturnal again.

Anyway, sorry that others are experiencing the same disappointment with the daylight behavior but I hope they are all healthy and none the less!

I may put the blue light on it's lowest setting (maybe 5-10% brightness) tonight and sneak out in the middle and see if they are now night-time foragers. I have a multi-colored LED - I could do red on super low brightness if that's better than blue. Thanks for the idea.

 

I hope you see them come out! I had to sit very still for a while before they started moving about. They have the BEST vision! They can see me coming as soon as I enter the doorway 10 feet away from the tank! Even in low light, they can see me! Makes me wonder about the other fish and shrimp in there, they can obviously see me but they don't care! Haha!

I love kribs by the way, had them a long time ago, but I suspect they will demolish the cherry shrimp I have.

 

They won't demolish the cherry shrimp. They will just be well fed.

I love kribs by the way, had them a long time ago, but I suspect they will demolish the cherry shrimp I have.

 

Just a quick update on my tank. My pigmies are all still hiding at the back of the tank and I suspected that they went nocturnal on me. So I camped out in the dark with them till my eyes adjusted and had a very low red light way in the back of the room so I could make them out, and yes the pigmy's were out and foraging. During the day they are on alert and when they see me walking into my office (where my tank is) they slowly move to the opposite side of where I am. It used to bother me but not so much anymore. As long as they are healthy I'm happy.

I honestly think they are very impressionable. Like if one of them is really skittish, then it infects the rest of them with the same sort of behavior. As an example, I recently introduced 4 green corys into the tank, and they are always busy foraging. When they come near the resting pygmies, they all start going tail up foraging too! It's kind of funny. It doesn't always happen but it happens enough to notice it.

I also have about 40 ember tetras in the tank as well that school 99% of the time. I was hoping that they would serve as a dither fish and encourage the pigmies to come out and school as well. It happened for a little while and then they pygmies when nocturnal again.

Anyway, sorry that others are experiencing the same disappointment with the daylight behavior but I hope they are all healthy and none the less!

I was going to suggest dither fish, and sure enough you added some other corys and they felt safer.

I bought some kuhlis thinking id probably never see them... but my friendly cory gang encourages the kuhlis to come out even in the day.

The corys used to hide when I had other larger fish, now they are the most "aggressive" and largest fish in the tank and will forage at will. I think the kuhlis reciprocally encourage the corys to come out.

 

Blue light on 1% experiment - saw 1 foraging and 2 glass-surfing. The rest? No idea. Thought about re-arranging. Not because I need or want too, but to see if they are somehow hiding under things as I don't see them behind anything. It's like they disappear during the day. I was encouraged that the 3 I saw looked fat so at least they aren't starving!

 

As Carpio said, I too think they're very impressionable. The first set of hastatus corys I ever got were not at all skittish. The next set I got had several skittish ones, and when I finally added them to the first set after QT, they all became skittish - including those that hadn't been previously.

I've seen it with other fish as well. I added a very bold schwartzi from the pool (it would come up and eat cubed tubifex right out of my hand) to a smaller tank of very shy schwartzis, and sure enough - it immediately modeled their skittish behavior, and stayed that way even when fully accustomed to the new surroundings.

Also agree they can see you from way across the room. I can enter the room and initially see the hastatus midwater at the front of the tank, and as soon as they see me they're diving for cover. Mine generally will come back out for food even with me standing there, though.

I haven't tried them yet with generally bolder tank-raised species like peppered or panda, mostly because I know those would likely eat the eggs when the hastatus spawn. But it would be interesting to see if it makes a difference.

 

fyi: fishes have excellent eye site. Er this is not an observation but i've read a couple of papers that explain this fact. From what I've read it also appear that fishes see colour.

 

Can anything be done to make them more comfortable? (As I type this I looked over and saw one foraging around like I was never something scary. Just one.) Here's a photo from happier times:

 

I started putting a fish/shrimp feeder dish (clear glass about 2" across) with food in in it at night. I've tried bits of seaweed, various blanched vegetables, algae wafers and shrimp pellets (made specifically for shrimp). The next morning, if it's sinking pellets (Hikari micropelets and some betta pellets - both labeled "slow sinking") the dish is clean. Anything else is untouched. Occasionally I'll see a shrimp picking at a veggie or if I put the snail on it, she eats it for a few minutes before going for biofilm on the sides of the tank. Nothing in the tank will eat specialty shrimp food, seaweed, or Hikari algae wafers at all. I even took some zucchini and smashed the pellets into it. It was picked clean, but no one ate any zucchini.

Now my only question is - are the pygmy corys eating it, or the shrimp, or both? The tetras seem to ignore it if it isn't floating. I need to set up a hidden night-vision cam.

 

Sorry in advance for the long post! Haha

I'm not entirely convinced that the pygmies are not comfortable or happy. I think as smaller fish they tend to be skittish in general. However, this article helped me glean some behavior observations about my hiding pygmies. Basically, they like shady areas. My tank is heavily planted but because it's heavily planted I have a really bright LED light on for like 12 hours a day. They must really hate that. They always hide in the darkest shade that my tank has. I think that either my LED lights are just too much for the little guys or they are on for too long. Or both. Either way, I don't really have the option of changing my lights, nor do I want to. I think they are happy enough as I do see them venturing around every now and then. Honestly, it's rare but it does happen.

I also think that my pygmies were wild-caught. Which I have mixed feelings about but my point is that being wild they are even more skittish than normal. So you may have wild-caught ones too!

I also think that their vision is so good that my office through the glass must look like an open ocean to them! So they back away as deep as possible away from the wide-open place. When I try to think about it from their perspective, they must feel like they are standing on the edge of the grand canyon all time, which a giant moving back and forth, poking its head into their space every day. Having a clean tank is a disadvantage here? haha!

Here is a funny story, I had a hanging breeder box on the side of the tank a while back. I was trying to save my blue shrimp babies as I trying to get my colony going. I was growing them out for about a month and then I would net them and put them back into the tank. While I was netting the shrimps I noticed a fish in there. It was a TINY TINY pygmy cory! My cories mated and the fry somehow got sucked up into the breeder box! Crazy thing is, this happened before but with my Golden White Cloud Minnows! Anyway, I put him back into the tank and he's survived just fine. In fact, I think because he/she's tank raised, he is actually the boldest of the whole group. He still hangs with the group in the back but he ventures out regularly.

Anyway, the article I linked says to have more shade overall. But I think that they will just have more places to hide! Haha! I'm not sure if my pygmies will ever school like they did when I first got them. I think they were in exploration "find a new safe home" mode. And now that they found the places they like to hang out they are happy just hanging out there! Haha! Anyway, I still love the little guys, I even have a video of them schooling when I first got them. They were incredible! But yeah, they may never go back to that.

Oh, and pygmy cory eats the small/nano fish granules/pellets that eventually fall to the ground. So yeah I think your cories are eating some. But my shrimp and snails polish off the extra.

ALL my fish and shrimp hate actual veggies. I watch all those videos of people feeding their shrimp various veggies and mine absolutely hate them. They will not touch them so stopped trying.

 

Have you tried fasting them on occasions?
Small schooling fish like C.pygmaeus don't always come out if they don't feel the need to leave their comfort zone.
Fasting once or twice a week can make a big difference in their daytime behaviour

 

Sorry in advance for the long post! Haha

I'm not entirely convinced that the pygmies are not comfortable or happy. I think as smaller fish they tend to be skittish in general. However, this article helped me glean some behavior observations about my hiding pygmies. Basically, they like shady areas. My tank is heavily planted but because it's heavily planted I have a really bright LED light on for like 12 hours a day. They must really hate that. They always hide in the darkest shade that my tank has. I think that either my LED lights are just too much for the little guys or they are on for too long. Or both. Either way, I don't really have the option of changing my lights, nor do I want to. I think they are happy enough as I do see them venturing around every now and then. Honestly, it's rare but it does happen.

I also think that my pygmies were wild-caught. Which I have mixed feelings about but my point is that being wild they are even more skittish than normal. So you may have wild-caught ones too!

I also think that their vision is so good that my office through the glass must look like an open ocean to them! So they back away as deep as possible away from the wide-open place. When I try to think about it from their perspective, they must feel like they are standing on the edge of the grand canyon all time, which a giant moving back and forth, poking its head into their space every day. Having a clean tank is a disadvantage here? haha!

Here is a funny story, I had a hanging breeder box on the side of the tank a while back. I was trying to save my blue shrimp babies as I trying to get my colony going. I was growing them out for about a month and then I would net them and put them back into the tank. While I was netting the shrimps I noticed a fish in there. It was a TINY TINY pygmy cory! My cories mated and the fry somehow got sucked up into the breeder box! Crazy thing is, this happened before but with my Golden White Cloud Minnows! Anyway, I put him back into the tank and he's survived just fine. In fact, I think because he/she's tank raised, he is actually the boldest of the whole group. He still hangs with the group in the back but he ventures out regularly.

Anyway, the article I linked says to have more shade overall. But I think that they will just have more places to hide! Haha! I'm not sure if my pygmies will ever school like they did when I first got them. I think they were in exploration "find a new safe home" mode. And now that they found the places they like to hang out they are happy just hanging out there! Haha! Anyway, I still love the little guys, I even have a video of them schooling when I first got them. They were incredible! But yeah, they may never go back to that.

Oh, and pygmy cory eats the small/nano fish granules/pellets that eventually fall to the ground. So yeah I think your cories are eating some. But my shrimp and snails polish off the extra.

ALL my fish and shrimp hate actual veggies. I watch all those videos of people feeding their shrimp various veggies and mine absolutely hate them. They will not touch them so stopped trying.

Thanks for that. Will read the article. Also watched this YouTube video (link at bottom) and it had some good suggestions. I've got a ton of plants and my lights are set to 80% brightness and only on 6 hours a day (and thankfully the plants are thriving but the algae is almost gone!) There's a ton of shade. I keep 3 sides covered from 10p.m. until 10a.m. so it's really dark. Then from 10a.m. until 4p.m. they get ambient/indirect light from the room and window. From 4p.m. to 10p.m. the lights are on (that's when I'm most likely to be in the same room.)

All of that to say in the video he made a good point about having plentiful places to hide. I ordered some small cichlid caves and was going to do a minor re-scape and put 2 caves towards the front of the tank. Eventually they may start foraging out front knowing there's an easy hiding place or two nearby without spending all their time at the back. Will let you know how it goes and update with some photos when I can.

 

Update: I was at an LFS and one of the ladies there is both very knowledgeable AND very friendly (an excellent combo.) I asked her about the pygmy corys and was talking about my neocaridina shrimp population. She asked if they started hiding after I saw all the new young shrimp and I think she had a point. She said they may feel crowded due to all the activity. She said I could bring in any neos I don't want for an in-store credit. Anyway, I went from like 12 shrimp to 100 (it seems) within a couple of months. So today I'm going to re-scape and remove a bunch of shrimp. Some will go in my plant-grow-out bowl (3 gallons, filtered and heated) and the culls will go in the betta tank (he seems to ignore clear/brown shrimp). I hope to leave 10-15 in the tank and take 20-30 to the LFS. The vast majority of them are a deep navy blue. Some (only a few) are jellybean but not clear at all. A few look "rili" and still others, clear/brown.

I'll post before/after of the re-scape. Wish me (and my back and everything that aches after spending hours bent over a tank) luck!

 

Good luck my friend!

A small update on my pygmies! I noticed a nitrate bump so I did a big water change about a month ago. After the water change, all my fish were happy and swimming around like normal. However, a few weeks later, I noticed some spawning activity among the pygmy cories. A female is being escorted by about 4 males dancing around her trying to convince her to hide in the plants with them. So there are two groups doing this in the tank right now.

I'm honestly at a loss as to what caused them to swim around more. They are such a mystery to me. I will say that a lot of my plants have become floating plants and have covered a good 70% of my lights so the bottom is really shaded right now. They do seem to like that better.

 

Update: I was at an LFS and one of the ladies there is both very knowledgeable AND very friendly (an excellent combo.) I asked her about the pygmy corys and was talking about my neocaridina shrimp population. She asked if they started hiding after I saw all the new young shrimp and I think she had a point. She said they may feel crowded due to all the activity. She said I could bring in any neos I don't want for an in-store credit. Anyway, I went from like 12 shrimp to 100 (it seems) within a couple of months. So today I'm going to re-scape and remove a bunch of shrimp. Some will go in my plant-grow-out bowl (3 gallons, filtered and heated) and the culls will go in the betta tank (he seems to ignore clear/brown shrimp). I hope to leave 10-15 in the tank and take 20-30 to the LFS. The vast majority of them are a deep navy blue. Some (only a few) are jellybean but not clear at all. A few look "rili" and still others, clear/brown.

I'll post before/after of the re-scape. Wish me (and my back and everything that aches after spending hours bent over a tank) luck!

Congratulations on selling shrimp at the LFS. I've sold plants to one several times, and made my first shrimp sale a few weeks ago

 

I got what seems like 100 of them moved to the 3 gallon bowl, but it seems like there are still 100 more in the tank. And of course, the one cull that has avoided capture the whole time, eluded me once again. AND I forgot to take a "before" picture. It's a bit cloudy after about a 70% water change and moving plants so I'll put one up after the dust settles. We'll see if I accomplished anything.

 

Exercise in futility! So the bowl - I put a couple of grown plants in with a bunch of aponogeton and 2 dwarf lily bulbs to grow out with the shrimp. The room is 74-80 degrees at all times so I was going to order a heater on Amazon. But the lily bulbs were bad and within 18 hours all the shrimp gasping at the top of the tank. NEVER buy the Petco lily bulbs. The aponogeton bulbs are better. You get 4-5 in a pack and at least 3 grow. Every lily I've ever gotten from them has been bad. The TopFin bulbs at Petsmart have a much higher viability but they only come in variety packs with those useless water onion plants. Anyway, Got it all reassembled, plugged in the filter and nothing. The filter died (it was a tiny HOB). So I moved the shrimp back to the original tank and am over it and going to pretend I'm happy for a few weeks while I figure it out.
EDIT: Forgot to mention that 4 of the corys have come out of hiding. When I did the rescape I counted 8. No corpses! So they are alive and well. They are still skittish if I move, but I see at least 4 them daily!

 

Man, I feel your pain there, were any of the lily's good? Or you lost the whole batch?

Hey, at least the corys are venturing out!

 

Not from Petco. I've bought them 4 times, took them back 2 times and just threw the other 2 away. And by 2 I mean, 2 per bag s I tossed 4 bulbs. In one of the TopFin mixed bulb packs a lily bulb did turn into a huge beautiful very red lily. But the Petco ones have been nothing but trouble.

 

Good to know! Thanks for that tip!

 

Thanks everyone for this very informative thread. My pygmies seem to be in the midst of this ‘out and about to nocturnal transition’ (at least I hope they are!) and this was all quite helpful!

 

I’m literally in the same boat, 3 of my pygmies r hiding (had originally 4) and I got 3 more that are still active out and about but I’m afraid they will also soon be shy. All I gathered was a water change and more cover worked for more bravery. I’ll keep note and watch the video