Cory Questions



When people say cory's dig, does this mean they rummage around the bottom or that they will literally dig into the substrate? Will they affect roots? I believe Gerryd and Shoggoth keep these so I'd assume they're safe, but assumptions can hurt. :rolleyes:
Is 2 inches a typical maximum size? Would 8 in a 55 keep them and me happy, or would more be desirable?
I'm basically in need of a quick run down of corys from anyone that has the info. Thanks.


Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida

IME cories will dig into the substrate for food, but not like drilling a well...

They will point their snout/barbels at the food and shake vigorously with their head to pull out worms and such..

So, while they don't go deep, they can easily injure themselves with a sharp substrate...

You will see that their barbels are much shorter than usual if your substrate is too rough..

I can't think of many commercial that are bad this way unless crushed coral?

I have used flourite with no issues...

2-3" based on species but most SA cories are not that large..

They like company fer sure, so 6-8 is a min school in a 55.

12-15 would be nice based on how many/what type of other inhabitants, filtration, etc.

Remember that they need to be FED not just eating fish poop or some nonsense...I fed mine blackworms at times and other foods...

Most cories remain somewhat active in the tank (many more at night) and school well. Be careful of bottom dwellers/breeders (Apistos) that may not appreciate cories....

Some of the more common cories will easily breed and lay eggs in a community tank, but so far I have not seen any youngt survive, but eggs plastered all over....

You can also mix species, say 4-5 of 2 or 3 species, as for the MOST part they get along very well. I say MOST part as I am not familiar with every cory species :)


Substrate shouldn't be an issue, flourite on one side of the tank and onyx sand on the other.

Less than 2-3 inches for south american types? Awesome, sounds perfect. I could probably pull off the 12-15. With this tank I'm shooting for 1 "premier" animal, then shrimp and perhaps some column swimming fish but those are to be decided later. Maybe hatchets or cardinals.

These guys would definately get fed. I've got a ton of frozen food. Bloodworms, daphnia, brine shrimp..even "Emerald Entree" if they need vegetables. Where would a person acquire live blackworms from?

Any clue as to the reason none of the young make it, or is it predation?

Edit: Disregard about the blackworms. Found a few online sources but they seem a bit tedious to deal with. Frozen bloodworms seem like the way to go.
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Guru Class Expert
May 23, 2009
csmith;51061 said:
Any clue as to the reason none of the young make it, or is it predation?

Yep, I think it's predation.

I had found that most if not all of the eggs would be eaten within a few days in my (heavily planted) tank.
I had had to remove them to another container to hatch.

But when I was cleaning the filter a few months ago, I found a fry (Sterbai) in it.
So some egg survived.

Please examine closely every time you clean your filter.

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Lifetime Charter Member
Lifetime Member
Jan 15, 2009
After a few days of replanting, it's rather tough for them to uproot anything like swords, staurogyne, blyxa, limno, chain sword and such. Mostly just the staurogyne since it takes a while to root in. Lack of fry is probably predation. Tetras and shrimp will pretty much deal with the eggs unless you have lots of plants to deal provide cover. Once they're born, I usually don't see any fry until they're in the 3/8" or so but they could easily be hiding deep in the plants. Barbel damage does not seem to have been an issue with the flourite gravel, flourite sand, or pool filter sand. They seem to really like bulldozing into the pool filter sand. Breeding seems to happen at night but especially is more common after a water change with cooler water.