Help With an Aggressive Cardinal?

[Sammy S]

I had gotten a pair of banggai cardinals (not mated, I think they are opposite gender?? I asked my FS for that and he grabbed them...I'm not good at sexing cardinals) and everything seemed fine for the first week I got them (March 11th). Every time I turn around now, the male hunts the female down and literally attacks her. I had to move him two days ago into my QT tank, but all his color is drained and he's stressed...which makes me feel bad. The fish store I bought him from offered to exchange him for another, but it's an hour drive and I wouldn't be able o go until next week...

Is it possible if I reintroduce him he could...become unaggressive? Or should he stay in QT? It's unfortunately a bare bottom tank in case I have to deal with unwanted parasitic pests.


The main tank is a 34 gallon tank with a pair of ocellaris clownfish in there and some snails.

Thank you for all your help!!!!

 

[Sniperhank]

These cardinals don't always do well in groups. They can, but can end up going postal on each other if not mated pairs. I would give it a shot, the worst that will happen is that the fish dies...which it sounds like it is heading down that path in QT anyway.
Saltwater Aquarium Fish for Marine Aquariums: Kaudern's Cardinalfish - Captive-Bred

 

[Sammy S]

Thank, I woke up this morning and his color is back, I had just done a water change so he was probably freaking out with that.

The female is out and about since he left and besides a torn caudal fin, is doing much better since he was removed- she swims with the clownfish and they get along pretty well.


My fish store insisted they need a pair to get along- she will be okay with just the clowns?

 

[Sniperhank]

It should be just fine.