Ok… buying another group of Cory’s for another tank… so really what is the practical size group???

So in one community tank, I have 7 albino aeneus, and 2 black Cory’s ( the blacks were salvaged from another tank, that as not great for the Cory’s this seems like a really great number of fish… in another tank, I had 4 sterbai, a couple died over a year, so now only 2, but they are doing great, as just the pair.
In this new tank, I’m starting with 6, it’ll also be a community tank, not a dedicated Cory tank…also, these will be a variety of aeneus, although not albino
So, do you guys think it matters much, which type of Cory, and what do you think is a practical group size in 30 - 60 gallon tank???

This heavily depends on other tankmates. If you have a heavy bioload already, maybe not a lot to the group, and also if you have fish that favor the bottom level such as some types of cichlids, you may be iffy with how many to push your luck with as well.

If you have a higher bioload or have other bottom dwelling fish--12-15 tops.


If you don't and only have something like tetras up top, up to 20-25 isn't so bad if you like a big group, and depending on the size of fish you choose. Aenea get fairly good size, so I'd keep it closer to 20 tops.

My input here, "Black" cories are osteogaster schultzei, a separate species from aenea and should also have their own group because they can and will hybridize with your albino aenea. I would suggest perhaps getting more of those and putting those in with the sterbai instead.


Stocking is something that isn't too black and white but does need certain planning and precautions. Cories like a lot of friends, but they're also kinda dumb and don't understand territories of fish that might like personal space on the bottom level, such as spawning cichlids.

My black and the albinos don’t really shoal together

So in your opinion, 6-8 are not enough???

It's the bare minimum, I wouldn't go below that and ideally you should have that much of each species where possible.

If you want just the minimum sized groups, 6-8 is just fine, but you may find better behaviors with even more to the group. That goes for many shoaling species, though.

Cass has this right on stocking, 6-8 is a minimum for happy same species cory behavior. More is better if you have tank space. It's not that the different species won't get along. But you won't get the "full" cory experience as you'd seen or likely breeding (always fun). They can tell they're not the same kind & will act that way with only a couple.

What's that Canadian expression, "go big, or go home!" (a nod to Cass, lol).

Get as many as you can within reason. In the wild they move in pretty large groups and that is neat to see. One of my favorite experiences was when I had 65 large cardinal Tetras in a 75 gal. tank.

But it is also important to have the right footprint for any group. I had an experience where Ithought I was getting about 25 juvenile sterbai. What I was given were 50 breeders. I was set up fir the 25 and had to cram the big ones into a couple of tanks which combined would have been roomy for 25 juvies. The corys were so tightly bunched there were no dynamics as there was no place to move to any degree. They were all sold over the next few weeks.

When you get a nice group of one, seeing them shoal together is really neat.
Here's 14 out of my 15 hoplisoma paleatum group. They're still juveniles, not yet full size, but you get the idea. Bigger groups change their behavior for the better.

stop buying fish and breed the ones you have

I generally buy Corys in groups of 6, for budget reasons. But my longer term goal with them is to have groups of 15-20, after they breed. I wouldn't buy six if I weren't set up to give breeding a try. Then, I would aim for 10.

If 10 didn't fit in my tank, I would buy none.

I always apologize to the group of six and explain they need to grow a little and produce enough for a decent shoal. Given their long lifespans, they only have about a year of inconvenience before their hunter gatherer band turns into a proper sized group.

As I mentioned in my OP, I’ll be starting with 6, and would like to add another group of 6, if it looks like they are working in the tank… this tank has a white sand bottom, and I have some of the slate grey fish coming next week… will see what the weather does, if I can get more before it get too cold…

I have a Jehmco air pump coming to replace the one that went out in my big group of tanks… this week, so the Cory group reflects the lack of funds… I’d have liked to do a group of 10 or 12…

Magnum Man said:

lack of funds…

Click to expand...

If I had your money I’d throw mine away .