Cory Violence?

[spectrum]

I came to my tank today to find one of my peppered cories dead at the bottom of the tank , he (or she i wasnt sure) had a red mark on its mouth area and it looked as though on of its.. whiskers? (is that the right word) was missing. i havent seen any other fish attacking it, but i thought one of my other two cories might have done it, because they dont school or follow each other, so i think that means they havent accpeted one another. The remaining 2 seem fine but i was just wondering, CAN cories be aggresive?

 

[Truck]

no theyre not generally aggressive.

what substrate do you have and what are you water params?

 

[spectrum]

I have gravel (boo i wish i had sand, but i cant really change that now)
sorry, dont know my water params

 

[Truck]

you can easily change or even capp it, take your fish out put them in a bucket, with a heater and top the gravel with sand.

bad water quality, is one of the biggest causes of coryies barbels, becoming raggy.