They have good enough eyes to see us from that far away (but then humans are much larger..) I'm not sure if its coincidence of if he can see her. I have a female on my desk next to other males tanks, she's in a curved vase but basically in front of a males tan (by the corner). He's seen her and I think she's seen him but neither are going nuts over it (no change in behavior).

 

I've had my males closer to my female but angled and no change in behavior. I guess it depends on the fish though.

 

I've had males and females in divided tanks before with no issue. It could be completely unrelated.

 

Maybe its not that he sees the female but sees you somewhere else, messing with something else (other tank/feeding) "Not paying attention to me!" and trying to get some attention. That might be a bit of anthropomorphizing but if you have dogs and/or cats you'll know what I'm talking about... >.>

 

Thank you for the responses, everyone! You've helped put my mind at ease.



I have cats, and I've had dogs in the past. I completely get what you're saying, and it's actually crossed my mind, too. Yurei was the only fish for two months after Rakki passed, and I know he enjoyed having all the attention. When Rakki was still alive and I was paying attention to him, Yurei would always be on the side of his tank closest to me, dancing around and trying to get my attention. When he does have my attention, he alternates between showing off with his fins spread and wiggling as close as he can get to wherever my finger is on the side of the tank.

It's very possible he's jealous, the little dorkfish. Thanks, Aqua. I'll just have to make sure he gets plenty of attention every day.

 

I've found some males are simply more sensitive to the presence of another betta (whether male or female) than others. Your male's renewed interest in bubblenesting, as well as the fin biting, could definitely be related to the fact that his tank is in such close proximity to your female.

When I remove the card between my two males' tanks, both will very quickly start work on new bubblenests. I personally see it as a territorial behaviour as much as a breeding behaviour. The nesting could be your male simply marking out his territory against a potential rival.

The reoccurence of the fin biting could be coincidental, or it could be down to 'barrier frustration', redirected aggression, or plain old stress.

If you're concerned, put something up so that neither fish can see the other, and see if your male settles back down.