Short story and question: a while back I bought 12 sterbai cories. I put 4 in my 10 gal that also houses 3 L260s, 3 or 4 ottos, aand a couple sawbwa resplendens. The other 8 went into my 40 breeder with 1/2 doz each pygmy cories (hastatus and habrosus), 4 adult L046s, and 11 sub adult L046s. A week or so ago, I noticed that 2 of the cories in the 10 had tattered tails and top fins. I thought it may be the ottos, based on some things I have read. I put 1 of them in the 40, figuring it would be fine. I couldn't catch the other 1, so it stayed in the 10. Tonight, while feeding the zebras, I noticed 2 cories in the 40 have the same tattered tails and fins, only more so ! So my question is, do cories fight with each other, or am I missing something ? the only thing common to both tanks are a few assassin snails. Could they be the culprits ? I would think that highly unlikely, based on the difference in mobility. Anyone have any ideas ? I'm stumped. Thanx for any and all help. Sorry to be so long winded !