Blue ram aggression

He is prbably just establishing his dominence! Or he could be attempting to court her, their courtship may look somewhat violent sometimes as they constantly bump eachother and the male will go into convulsions, it is quite entertaining to watch! I added two Rams to my tank about 3 months after I added my first bunch and there was a bit of aggresion for the first week, while they established the pecking order, so this might just be the case! Give it a few days and if it doesnt start to settle down than you should take one back just to be safe! And you could even try another one as some just dont seem to be compatible with eachother but are compatible with others.

It might be a terrority thing. I have african cichlids and was told that if you are adding fish with to re arrange the tank and makes the adjustment easier and to add more than one to take some of the pressure off. do not know how this applies to rams though. just a thought.

Blue Ram

12 gallons is to small rams like room try a 20 gallon +

when they do spawn, they get an unnerving aggression. mine chase my discus to one side of the tank. they are bigger than a CD

If you only have a 12 gallon I would take the female back and just enjoy one of them. If he is being agressive, she wont servive. If he's trying to court and they are succsesfull, your other fish wont servive. (this is assuming that you have a male and female) If you have 2 of either sex then they will never get along.

Well, you could hold off a bit and just wait and see what happens. Mine go through periods where if I didn't know any better, I'd remove one or the other because of the aggression between them....but it always settles down after a bit and they both color up nicely. Right now my male is the dominant one and the female looks possitively white. They switch on and off...lol...next time he'll get his due, I'm sure. I have them in a 29 however....I do have a friend who has a pair in a 10 and it's working out for them, but that is pretty small for rams.

As far as the other fish in the tank go, they don't usually bother others too awful much, at least mine don't. They are very good at keeping other fish away from their "spot", but they don't harass the others to the point of damaging them. Usually just a quick dash at them and then back to thier area.

Fully grown they are 3" big. Having more then one in a 12 gallon might be pushing the envelope. I have 3 in a 75g, one chased the other 2 for a week or so but eventually they got along. Watch them and see. They are sensative and need clean water or they won't servive, IME.
good luck.