Bangai Cardinal Aggression

I have 2 bangaii cardinals in my tank as well as several other fish.

Cardinals used to like each other and swim together for 2 month + they been in my tank.

But last couple of days one of them keeps chasing another and nipping on it's fins. The other gave up on swimming and just hides in various small holes and would not even come up to eat.

*sigh*

Thinking about taking the aggressive one back to LFS.

Any other ideas?

What causes change in behaviour like this?

Thanks.

 

You either have two males or two females. They get along fine when they're juveniles but once they become adults, it's aall out war.

 

I imaging reproductive maturity and territory issues as they get older, leads to the aggression. Seems like a 55 gallon tank would be enough room to prevent this, but fish are just weird sometimes.

I think taking the aggressor back is the best option, the fish might start messing with the others as well.

I do not know how they act when brooding eggs and fry and that might account for it.

 

Came home today and 2nd cardinal (the one that gets picked on all the time by the *****) is missing half the caudal fin. That was the last straw.

After 45 minutes and some elbow grease, ******* evicted. Took him back to LFS.

Will the fin ever grow back? Or is my other guy maimed forever?

Thanks.

 

Yeah 2 males, Bangai males will fight to the death. You can have a male and a female, but they are difficult to sex. I think 2 females can also do ok, but never 2 males.

Unfortunately I can't say if the fin will grow back. Should, but depends how bad it is and whether or not it gets infected.

 

it should grow back. ive seen fish lost 90% of tail and other fins and they grew back. they can e more resiliant than we think. sorry to hear it.

as for the zexing of them, as juviniles they can be very hard. the mail usually has a much longer rear dorsal tip. it is almost pure black. once sexually mature, the male will have a more pronounced Jaw line (think JOCK) and the 2nd pectoral will be much longer than the females. I can tell I have a male in my tank. need to get him a girl or two.

 

Thanks. I think both of mine were males but somehow got along just fine for 2 month.
If i get another cardinal, ill make sure to get a female.

 

I thought these were ok in groups. I was thinking of getting 4 or 5 for my 150 - bad idea?