Scared Cory

[lm118]

Hi, I have 6 Corydoras trilineatus in an established 70 litre tank for about a month.
 
There are 5 small ones, and one which is quite a bit larger, and looks to me like an older female.
 
The other 5 seem really happy and swim all over the tank, not minding me at all, but this bigger one basically sits in a dark corner under some plants all day, and will completely freak out if I come too close to the tank quickly or make any sudden movements.
 
When I got them the shop assistant said he'd been trying to get the bigger one, so all I can think of is that this stressed the fish out massively, and it's not recovered. Also this fish is rounded and quite fat, I was wondering if females full of eggs are more likely to scare easily?
 
I've put real plants in the tank, and coconut caves to hide in, and don't know what else I can do. When I sneak in the room the tank is in the bigger fish is often swimming happily along with the other corys, but stops as soon as it realises i'm there!
 
Any advice would really be appreciated!

 

[DiddleBug]

I had the same problem.  And yes, my big gravid female seems to be quite shy at times.  The best thing to do if you want to watch them is to just sit down and wait for them to come out.  They can feel vibrations when we walk around and they can get scared easy. Try it in the evening or after you put in food.  Mine get quite bold when I drop in food, they don't seem to mine me so much.  Sometimes I walk around the room in slo mo or tip toe for them.    Corys are just more shy than other fish, as they are most active at night in the dark.  Don't worry too much.  They should start feeling more at home too as they adapt to their new surroundings.  

 

[eaglesaquarium]

The questions that leap to mind are: 
 

• How much cover is in the tank?
• What other fish are in the tank?

 

•  Then the biggest thing is this:  Are you sure that they are ALL trillineatus? 

I bought 4 cories a while back thinking they were all the same species, but it turned out that they were different sizes, not because some were older, but because they were different species.  The one that wasn't the same species hung out by itself.  They had identical markings.  But, the differences were there just not in the obvious ways.... There were more subtle differences.
 
 
1 was a trilineatus, the others were all leopardus.  I'd ask that you post up pics of the different species.  It will make it easier to identify if they are truly the same or if they are actually different species.

 

[Pugsnstuf]

Hi, I have 6 Corydoras trilineatus in an established 70 litre tank for about a month.

There are 5 small ones, and one which is quite a bit larger, and looks to me like an older female.

The other 5 seem really happy and swim all over the tank, not minding me at all, but this bigger one basically sits in a dark corner under some plants all day, and will completely freak out if I come too close to the tank quickly or make any sudden movements.

When I got them the shop assistant said he'd been trying to get the bigger one, so all I can think of is that this stressed the fish out massively, and it's not recovered. Also this fish is rounded and quite fat, I was wondering if females full of eggs are more likely to scare easily?

I've put real plants in the tank, and coconut caves to hide in, and don't know what else I can do. When I sneak in the room the tank is in the bigger fish is often swimming happily along with the other corys, but stops as soon as it realises i'm there!

Any advice would really be appreciated!

How is mama Cory now?

 

[AdoraBelle Dearheart]

How is mama Cory now?

This thread is seven years old...

 

[Essjay]

...and lm118 has not been on the forum for 6 years.