Suspicious Giant Danios

Question
I have a 5 gallon tank with 3 giant danios and a swordtail fish. (I know that the tank is slightly too small of for these fish). Anyway, I've had the danios for over a year now. I used to have 4, but one died of swim bladder (I had him seperated, but he died anyway.) Anyway, recently two of my giant danios fins have turned red, and they have started randomly fighting. Just those two fish. The other two don't get involved. The fighting seems pretty intense. Any help you can give me would be great!

Thanks,
Rin

Answer
A little too small is an understatement. More like 6x too small.


But anyways....your danios need to be in schools to prevent agression. You should have at east 5 or 6 danios at one time, but since you can't keep them in a tank that small there is no real solution but to buy a bigger tank.