Betta attacks rummy nose tetra

[spacecowgirl]

Hey everyone,

Iv'e had my tank for over a year now (20gallon), and all my fish are fine (6 rummy nose tetras and a betta). Water parameters are fine, it's planted (plenty of shelter and hiding spots), there's air pumps, suitable gravel/substrate, all my fish are disease free and get along fine. However, today I saw my betta fish attack my rummy nose tetra, it was plucking it's eye out and had evidently removed the other entirely... My poor rummy passed away almost immediately, but I just don't understand what got into my betta? There's a suitable school of tetra's, and they don't bother each other and never have done. My fish are all fed suitably, does anyone know why this could have happened? Could it have just been a fight?

Thanks in advance.

[mommy1]

Could it have just been a fight? No. Your betta has decided he doesn't like the rummys and it will probably just get worse. A lot of people put incompatible fish together and think it is fine because it works for a while. What they don't realize is fish don't usually come into their true nature until they mature. Your betta is now a mature fish and probably wants his own space. It would be best if you get a 5g set up for him and leave him in it by himself.

[Triton]

Could the betta just have been eating a fish that died of other causes?

[spacecowgirl]

Could the betta just have been eating a fish that died of other causes?

Hey, thank you for replying, no the tetra was perfectly healthy, in fact all the fish were.. It was literally attacking the tetra violently (sorry to be graphic) before I intervened, however, it was too late.

[spacecowgirl]

No. Your betta has decided he doesn't like the rummys and it will probably just get worse. A lot of people put incompatible fish together and think it is fine because it works for a while. What they don't realize is fish don't usually come into their true nature until they mature. Your betta is now a mature fish and probably wants his own space. It would be best if you get a 5g set up for him and leave him in it by himself.

Thank you for your response. The thing is, iv'e been observing him since the incident and he hasn't attacked any of the other fish.
Secondly, I did do my research and although the personalities of betta fish vary, they tend to do be compatible with fast swimming and agile fish, like the tetra, that does not have long flowing fins.
Before I bought this betta, I visited the local fish store numerous times over a course of three weeks, this particular betta was housed in a tank full of rummy nose tetras and was doing perfectly well. But I appreciate your advice, I will have to do somethings urgently, perhaps return the betta if possible.

[Aeonflame]

Temperament may vary with bettas. I've seen some particularly aggressive ones that did not tolerate any other fish in their area. It may happen again or it may not. Your only options are to rehome it or wait and see.

[vafa]

Well with my experience this has happened multiple times with multiple fish.
For me after the incident all other fish go back to normal. This happened with my betta, platy, ram, and kribensis and I've never found a reason to it.
I would just watch closely for the next few weeks and see if you need to re home it

[Tetraodon]

Temperament completely varies in bettas - some will happily live with anything, some have to live alone (and will even attack their owners!). As they mature they can show their aggression a lot more. I've personally had luck with betta temperament, but I know others who can't keep them with anything living (or it won't be living any longer).
It could have been the rummynose was slightly ill and that it attacked it, but to be safe I'd probably keep it solitary. You could keep it in a while longer and keep an eye on it, but you would need to be very prepared to remove it as soon as it shows any aggression.
How many hiding places does he have? I find bettas do best in a heavily planted tank, with lots of places to hide and break "line of sight". It'll keep the rummynoses feeling safer, too.

[Faded]

Bettas are a very unpredictable fish. You can think they are non-aggressive one day, but then the next day you will find a fish dead. With such a diverse personality, you can never be 100% sure how well your betta is working with other fish.

The only things I'm pretty sure have the highest chance of working without flaw is keeping a betta in a 40 gallon or larger tank that is highly planted(meaning a lot of hiding spots as well) with very large schools of hardy fish(16 or more). I've even seen this with more than one male betta before.
Also, small and hardy bottom feeding fish, such as some corydoras, have a high chance of being successfully kept with bettas, provided hiding areas.

[spacecowgirl]

Bettas are a very unpredictable fish. You can think they are non-aggressive one day, but then the next day you will find a fish dead. With such a diverse personality, you can never be 100% sure how well your betta is working with other fish.

The only things I'm pretty sure have the highest chance of working without flaw is keeping a betta in a 40 gallon or larger tank that is highly planted(meaning a lot of hiding spots as well) with very large schools of hardy fish(16 or more). I've even seen this with more than one male betta before.
Also, small and hardy bottom feeding fish, such as some corydoras, have a high chance of being successfully kept with bettas, provided hiding areas.

Thank you for your response. Unfortunately as a student, I don't have the financial means or space to purchase another 40 gallon aquarium, or indeed another aquarium as my 20 currently sits in my bedroom. Iv'e followed the general consensus of seeing what happens, and unfortunately my betta has gouged the eyes of another rummy and killed it... dreadful. I now have to get rid of my betta, I don't really have another option.

[spacecowgirl]

Temperament may vary with bettas. I've seen some particularly aggressive ones that did not tolerate any other fish in their area. It may happen again or it may not. Your only options are to rehome it or wait and see.

Hey, thank you for responding. I guess rehoming is my only option, I waited a few days as recommended and he seemed fine. However, he's just gouged the eyes of another tetra and killed it. Is there a reason he's going for the eyes? Sorry to be graphic.

[pRED]

Is there a reason he's going for the eyes? Sorry to be graphic.

The eyes are the windows to the soul. Your betta is the Devil! :18:

[mommy1]

Well, like I said, once it starts, it probably isn't going to stop. I suppose he is going for the eyes because they are an easy target, but really who knows. Check Craigslist or its equivalent in your area, sometimes you can find complete set-ups pretty cheap. One betta will only need a 5g.