Cory behavior -- will they stop pacing?

[Mattjm20]

Hi all,

I've got a 90G tank and I'm pretty happy with things, except that my 4 Sterbai corys won't stop pacing up and down the side glass like maniacs. Can you tell me if this is normal, what I can do, etc? As a quick note, I plan to get a few more sterbai corys, but the LFS ran out so i bought the 4 that they had. Does anything think making it a solid half-dozen would make them act a bit more normal?

Here's info about my tank:
- all nitrites/ammonias at 0
- started with the temperature in the mid 70's, not it's at abot 79... that has not changed behavior
- PH was slightly above 7, but I added some fluval peat granules to my canister to soften things up a little bit
- running a fluval 406, i've varied the current output and that hasn't changed behavior
- lots of plants and driftwood... there are no shortage of hiding places
- The corys have paced before i added anything else by my 2 Bolivian rams, so I don't think this is a factor but my stock includes 10 neon tetras, 6 black neon tetras, 2 bolivian rams, 1 apisto cacatuoides, 1 SAE, 5 juvenile boesmani rainbowfish, and then the 4 sterbai corys

Can anyone help?

[jimoo]

Doesn't sound like anything to worry about. I've had Corys and other fish do similar things when just added. They chill out after time.

Just a minor thought though, if you have a light/bright window shining on that side of the tank it might create a mirror type reflection in the tank.

[syno321]

[quote="jimoo"]Doesn't sound like anything to worry about. I've had Corys and other fish do similar things when just added. They chill out after time.

Just a minor thought though, if you have a light/bright window shining on that side of the tank it might create a mirror type reflection in the tank.[/quote]

This is a good point. As well you might want to consider what substrate you've got in the tank. Too sharp and they might not want to be on it.

[Mattjm20]

Thanks all and merry Xmas!

I am using Black Diamond 40-60 blasting sand. It definitely doesn't appear to be too sharp and I researched feedback from other Cory owners before buying.

There does appear to be some reflection on that side from my perspective but I can't tell if that's what they are seeing. Also, they even do it when the light is off so I'm not sure that's it.

[FerocactusLatispinus]

I've found that when there's an outside light source, when the tank lights are off, my corys always choose to sit as close to the bright side of the tank as possible; all my other catfish avoid the light, especially the Synodontis cats. My corys are more or less crepuscular than nocturnal or diurnal (I think this is the nature of most or all corys, though).

I also was worried about the sharpness of the substrate when I was considering sand over gravel. All my fish have seemed to not be affected at all by the pool filter sand I had washed and switched in. Even the banjo cats' eyes, fins, or bellies are scraped up at all. The sand is quartz, of course, and that's what glass is pretty much made up of, so I still get a little concerned once in a great while when the corys seem to "choke" on some food/sand grains. They always turn out fine though, and aren't clamping their fins or scraping themselves all over the place when this happens; maybe they're just doing some extra filtering once finding food.

My corys always paced back and forth in the tank when I first introduced them, especially along the glass. They still do, but they almost always do it whenever I approach the tank: they also frequently try to race up the current from the external filter as a form of exercize!