Sand size for pygmy corys

ellejay

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Hi there. Currently cycling my 64l tank and planning to get some pygmy corys once it's ready. I bought black sand but I'm worried its too coarse for them - it's about 1-2mm (pack doesn't give actual size, I had to measure) and seems a little sharp to me. I put it in anyway, thinking it wouldn't matter since they dig less than other Cory species, but I'm starting to have second thoughts and now would be a good time to change it out if it's not right.

If I need to change it what would be a good alternative? I've use playsand before but would prefer something different this time. I do like the look of black sand.

Thanks :)
 
What type of sand is it and can you post a photo?

As for if you decide to change it, I like BDBS(have it in 4 tanks) with the 20/40 grit. I house cories on this as well.
 
What type of sand is it and can you post a photo?

As for if you decide to change it, I like BDBS(have it in 4 tanks) with the 20/40 grit. I house cories on this as well.

You seem to be my personal fish guru today!

It doesnā€™t really say anything useful on the pack, just pets at home black sand. It feel more like fine gravel to me. Iā€™ll get a photo...

BDBS is the blasting sand right? Is it easy to get hold of?
 
Try play sand - Argos or B & Q. It is very safe, it has to be because small children will try to eat it, and it is smooth. Play sand is also cheaper than sand sold at fish shops. Blasting sand has to be sharp to do its job and sharp sand is not good for bottom dwellers like cories as it can cut their mouths.
 
You seem to be my personal fish guru today!

It doesnā€™t really say anything useful on the pack, just pets at home black sand. It feel more like fine gravel to me. Iā€™ll get a photo...

BDBS is the blasting sand right? Is it easy to get hold of?
Yes, you can typically find it at a tractor supply or similar store. Itā€™s goes for around $10 for 50 lbs.(at least when Iā€™ve purchased it)
Try play sand - Argos or B & Q. It is very safe, it has to be because small children will try to eat it, and it is smooth. Play sand is also cheaper than sand sold at fish shops. Blasting sand has to be sharp to do its job and sharp sand is not good for bottom dwellers like cories as it can cut their mouths.
I havenā€™t found mine to be sharp and have kept my cories on it for several years now without incident. A number of other cory keepers(and breeders) also keep them on this substrate without issue.

Play sand is a nice option as well, but it will take quite a while to clean. Iā€™ve found that BDBS cleans typically within 3-4 rinses. Pool filter sand is another option as well.
 
296C76EE-E140-4EFA-B9B9-FD42E9C446FE.jpeg

Sorry, that took me a while, struggled to change the file size on my phone.
 
Oh yeah thatā€™s definitely not sand sand. You said it feels sharp? Iā€™d be a bit wary of that myself. If it isnā€™t to sharp it should be ok, but if it feels sharp I wouldnā€™t use it.
 
Hmm I knew I shouldā€™ve returned it. Ah well wasnā€™t too expensive and wonā€™t be too difficult to remove with very little else in the tank.

Try play sand - Argos or B & Q. It is very safe, it has to be because small children will try to eat it, and it is smooth. Play sand is also cheaper than sand sold at fish shops.

Iā€™ve had playsand before, looked nice enough but I fancy something different. Itā€™s not a huge tank and itā€™s my only one so donā€™t mind spending a little more. I will keep it in mind though
 
For pygmy cories, sand is frankly essential. I have discussed this with all the global cory authorities. Sand and cooler temperatures (75F/24C max) is essential for the three "dwarf" species.

Play sand is without question the safest and best sand for cories. My 10g has a group of pygmy cories that spawn regularly and have been for six years now, and fry appear regularly and develop well.

Blasting sand should never be used in aquaria as it can be sharp--it is intended to be sharp in order to do the industrial job. Pool filter sand can work sometimes, but not white as this bothers fish. The black aquarium sold in pet stores might be OK (if it is the true sand) but very expensive.
 
For pygmy cories, sand is frankly essential. I have discussed this with all the global cory authorities. Sand and cooler temperatures (75F/24C max) is essential for the three "dwarf" species.

Whatever I get it will most definitely be sand. This is the sort of thing I had in mind https://www.allpondsolutions.co.uk/black-0-6mm-5kg-60kg/

However, if playsand is really whatā€™s best I will go with the expertsā€™ opinions.
 
Whatever I get it will most definitely be sand. This is the sort of thing I had in mind https://www.allpondsolutions.co.uk/black-0-6mm-5kg-60kg/

However, if playsand is really whatā€™s best I will go with the expertsā€™ opinions.

I would want to see and handle the linked substrate, but given it says "gravel" and also from the photo I would think this is not going to work. I came across some "river gravel" several years ago in a local fish store, and while it was very small in grain size I would never put cories over it due to the angularity and roughness.

The reason I so often recommend play sand is simply because it is so safe to use in aquaria. Play sand is the most highly refined of the industrial sands. Cories like to take up mouthfuls of the substrate, sift out any food tidbits, and expel the substrate out through the gills. Only sand or mud allows these tiny fish to achieve this, and without damage. It does take a lot of rinsing, though I do not go overboard with this; it is after all only dirt and that is not going to harm any fish, and it will settle out fairly quickly.

By the way, I saw this mentioned in your other thread on stocking, but as it pertains to the cories I will mention it here too, that this species (Corydoras pygmaeus) is always better with a larger group. I would aim for 8-10. Five is generally considered the minimum for the larger species, but the dwarf species will fare better with a few more.
 
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I would want to see and handle the linked substrate, but given it says "gravel" and also from the photo I would think this is not going to work. I came across some "river gravel" several years ago in a local fish store, and while it was very small in grain size I would never put cories over it due to the angularity and roughness.

The reason I so often recommend play sand is simply because it is so safe to use in aquaria. Play sand is the most highly refined of the industrial sands. Cories like to take up mouthfuls of the substrate, sift out any food tidbits, and expel the substrate out through the gills. Only sand or mud allows these tiny fish to achieve this, and without damage. It does take a lot of rinsing, though I do not go overboard with this; it is after all only dirt and that is not going to harm any fish, and it will settle out fairly quickly.

By the way, I saw this mentioned in your other thread on stocking, but as it pertains to the cories I will mention it here too, that this species (Corydoras pygmaeus) is always better with a larger group. I would aim for 8-10. Five is generally considered the minimum for the larger species, but the dwarf species will fare better with a few more.

Ok I'm beaten down, I will go with the play sand! 8-10 pygmy corys is the plan; I love juliis but think it would be a bit ambitious in this tank (64l) and I'd rather have the biggest group I can in the space I have.

I'm cycling my tank at the moment, would it upset the process to change out the sand now or should I wait until its done? Only just started really - this is Day 4.
 
You can change out the sand wherever you like, it may actually be better to do it early on in the cycle so no issues arise closer to when youā€™ll be adding fish. Changing the substrate can occasioanlly cause a mini cycle.

Iā€™m still rather certain BDBS would be fine, Iā€™ve kept cories on it for years and so have many of my fellow aquarists, but Iā€™m sure the playsand will look nice and work well too. Just donā€™t try to get anything else done when you plan to be rinsing it lol. Iā€™ve never used it but those who have say it takes forever to clean.
 
I'm cycling my tank at the moment, would it upset the process to change out the sand now or should I wait until its done? Only just started really - this is Day 4.

Change the substrate now. The greatest colony of bacteria of various species lives in the substrate, not the filter, and the substrate is actually the foundation of a stable biological system in any aquarium. It takes a few months to fully establish, so changing it now is better than later.

I have changed out the substrate in all of my tanks at least once, many two or three times, over the last 20 years. Once the tank is established after several months, this is less of an upset because there are bacteria living on all surfaces covered by water, and having live plants prevents any "cycling" issues anyway. But here you are dealing with a new tank and changing the substrate now will allow the tank to settle better over the next three or four months. Leave the filter (meaning, no cleaning other than rinsing in a bucket of dechlorinated water if necessary) so that bacteria colony will not be disturbed. And if you have live plants, especially fast growers like floating, you will not have cycling issues anyway. I never "cycle" tanks with floating plants; no need, and there is always the risk of harming the plants with ammonia.
 

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