All Of A Sudden Aggressive Beta

Hi, so I have a 10 gallon tank with a male betta and 2 cory cats. They've been together for about 2 months and everythings been fine. They've left each other alone for the most part. Actually, I've seen whay looked like, the betta and corys playing together. No flaring at all. So, all of a sudden about 3 days ago, he became super aggressive and very skitish. He sits at the top of the tank all day and sometime darts around the tank. He even flared at me tonight when I was feeding him. And yes he is eating. Hes usually very active and is happy to see me. After I turned the light out tonight he immediately started attacking the corys . The water parameters are fine, and nothings changed. I've read that when they are ready to spawn that they can act like that but I'm not sure that's it. If it keeps up I'll have to remove the corys but would love to be able to keep them together. Any help or advice would be greatly appreciated.

 

Just a warning people are going to tell you the Cory cats need to be in groups of 6+ and need a 20 long tank, not true. I have a setup just like you and have been doong a study for about 5 months between corydoras in big groups and and large tank vs. a small tank and in pairs or trios and the ones in “small” tanks in pairs do better then the rest, mentally and physically. To solve your problem just put the Betta in a separate QT tank for a week+ then put him back in but add a couple new decor pieces to the tank with the Cory cats to make it look different.

 

have been doong a study for about 5 months

What do you mean? Do you even have a large group in a large tank?

They really do need a group of 6 at the very least. This isn't the problem though. Bettas can (not always) turn mean, it's their nature that was bred into them

 

I have 2 corys and they're happy as can be. I'm no expert but they seem very happy.

 

What do you mean? Do you even have a large group in a large tank?

They really do need a group of 6 at the very least. This isn't the problem though. Bettas can (not always) turn mean, it's their nature that was bred into them

Yes I do I have 7 (I think) in a 40B and two in a 10 gallon with a Betta

 

I'm just confused on why all of a sudden this change in behaviour. Like I said, they've been very happy together until a few days ago.

 

I'm just confused on why all of a sudden this change in behaviour. Like I said, they've been very happy together until a few days ago.

Sometimes it just happens it’s in their nature but if you remove him for a week+ then put him back in that should help. What kind of male Betta is it?

 

I'm sorry, I don't even know.

Could it be that he's ready to mate, make bubble nests, and is just being territorial ?

 

Could it be that he's ready to mate, make bubble nests, and is just being territorial ?

Maybe but I’ve had my male make bubble nest in his 10 gallon with the Cory cats and he still “played with them” like he usally dose.

I'm sorry, I don't even know.

Pictures?

 

Sure but the lights are out for the night. I'll send in the morning .

 

Sure but the lights are out for the night. I'll send in the morning .

Okay that’s fine I may not respond until afternoon because I have horse riding

 

Yea, mine seemed to play together to. That's why I'm confused . I'll try to quarantine him for a week and If that doesn't work I'll have to get rid of the corys . Id really hate to though.

 

Mine was fine with 2 Ghost Shrimp for over a month. They had doubled in size so had to have molted a few times. Last week, in the span of 3 days, both shrimp disappeared. I caught the Betta eating some white meaty stuff right next to a shed shrimp shell. He had been getting annoyed with them going to the surface when it was his feeding time and had chased them a few times. One day he snapped at one and the shrimp grabbed on to his tail and wouldn't let go. Benny was swimming around frantically trying to shake it off and finally managed to do so. Maybe that was the last straw but it was at least a week before they disappeared.

Yes, they were true Ghosts. They both had the red bands on their feelers and front legs and the red spots on their tails.

Do your Corys ever go near the surface of the tank? Bettas seem to get more territorial about the top of their tank. My guy doesn't always feed at the surface though. He often picks at the plants and gravel looking for food because he knows what is put in for the snails winds up down there.

 

They go to the surface to gulp air but that's about it. They may have run into him or nipped him in fun and he just got tired of it . Not sure.

 

They go to the surface to gulp air but that's about it. They may have run into him or nipped him in fun and he just got tired of it . Not sure.

Like I said, Bettas get more protective of the top of the tank because that's where they build their nests. One day I noticed my Betta flaring at and even nipping at my Nerite snail who was near the surface. He had never done that before. Then I saw Benny blowing some bubbles against the side of the filter box and realized that the flaring and nipping was just instinctive nest protection behavior. When the snail went back down he was once again totally ignored.

 

Like I said, Bettas get more protective of the top of the tank because that's where they build their nests. One day I noticed my Betta flaring at and even nipping at my Nerite snail who was near the surface. He had never done that before. Then I saw Benny blowing some bubbles against the side of the filter box and realized that the flaring and nipping was just instinctive nest protection behavior. When the snail went back down he was once again totally ignored.

That's one scenerios I was thinking. He's ready to make his bubble nests.

 

Rearranging the tank can help with aggression for a short period of time.