Nutter

I have a 3x1.5x1.5ft planted community tank that has 3 x Otos, 5 x Khuli Loaches, 1 x Peppermint Bristlenose, 10 x Cardinal Tetra, 3 x Leopard Cory & 4 x Sterbai's Cory. The parameters are GH 9, KH 7, pH 7.2, ammonia 0, nitrite 0 & Nitrates vary between 10-20. It has a 3mm rounded gravel substrate suitable for softwater. The tank has been established for about 4 years with the most serious problem a dose of ICH about a year ago.

3 weeks ago I added 2 more Sterbai's Cory to the two that were already in there. Ever since the two new corys went in, all of the corys have been acting strange. They don't seem to want to be on the bottom anymore & spend most of thier time swimming up & down against the glass & around mid-water. They are essentially acting just like a nervous swordtail or platy.

Nothing has changed in the tank at all except for the two new corys & they seem to be in perfect health, no injuries or spots or anything like that & they are breathing normally. At first I put it down to just needing time to settle in but now I think maybe there could be something deeper going on.

Does anyone have any clue as to what might be going on? I'm stumped.

namehater

sounds to me like you have some happy cory cats!

Nutter

It's weird for what they usually act like. My ones have always been very big on sifting around through the gravel & just sitting on the bottom to have a bit of a snooze. The only time they ever really went of the substrate/decor for anything was to do the occasional trip to the surface to get an extra breath. From memory that's what the trips to the surface ore for with corys anyway!! My memory ain't what it used to be!!

Nick Goody

Could possibly be that now they're in a larger group they feel more secure about leaving the bottom of the tank? I have a group of 5 in one of my tanks, 2 Bronze and 3 Peppered. They're always doing it.

Nutter

Maybe I guess. I'm just trying to figure out if it's something I should be worried about or not. I guess I will just monitor the tank & fish closely & make sure nothing develops.
Thanks for the replies.

Jaysee

I agree. They're just happy to be in a larger group.

eiginh

I agree with the all the suggestions. I don't think you have anything to worry about. They're really happy that's what mine does in my 10g. Having 2 cory's only is pretty boring for them some suggest 3 should be the minimum but the real minimum should be 6 also suggested by others. I'm glad they have more family now

Jaysee

Couldn't agree more about 6 (of one species) being a minimum.

Melissawater

My cories always did that too, now my one cory still does it especially if I am in front of the tank looking at him!

Nutter

Cool. Doesn't seem like anything I have to worry about then. That's quite a relief. I wasn't much of a cory fan when the kids chose them but the little guys have grown on me.
Thank you for the replies. It's quite reassuring to know other peoples do the same thing.

eiginh

Glad you're relieved