6.6 "Bookshelf" tank

This is the first time I heard of threadfin rainbowfish killing each other. Male threadfins killing each other sounded so absurd to me. I had plenty of these before and they were barely an issue to each other.

Nice tank though.:)
 
No, they were Threadfin Rainbow fish, not bettas. Iriatherina werneri is their scientific name. And I've never read anything about them being aggressive, I choose them because the tank is small and I needed a small fish I could keep in it. I could support 6 -7 threadfins but all my lfs had were males (and not many at that) so I got three and one started beating up on the other two and eventually killed one of them.
 
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