Bangaii Cardinal Flake Food Issues?

[kooken]

Some info about the tank in question:

29 gal
s.g. 1.023
Ammonia, Nitrite: 0
Nitrate 5 ppm
pH 7.8 (low, I know.)
30+ pounds of live rock
The tank has been set up at my home since February 2006, and had been set up for a couple of years at a coworker's house
Filtration: Sea Clone protein skimmer, Magnum 350 for mechanical filtration
Inhabitants: 2 black percula clows, 2 Bangaii cardinals, 1 orange spot shrimp goby

My problem/question:

I have had the two Bangaiis in the tank for several months, and they have been eating flake food all along. I also sometimes feed Mysis shrimp and small bits of krill. One cardinal is a little longer than one inch across the body, not counting the tail. The other is about 3/4 of an inch across the body.

Last night, I put in the Formula One flake food, as I always do. The larger cardinal went to the surface, got some food, and then he started acting strange. He tipped sideways and just floated at the top of the tank, and it looked like he was struggling to breathe. I watched him closely, and after 10 minutes or so he seemed to be back to normal. This morning, the same thing happened, this time with both of the cardinals. They were fine, then they ate the flakes and both started floating/swimming sideways. The bigger one sunk down to the bottom and just laid there. The smaller one, turned sideways, just hovered above the live rock. Now, 10 or so minutes later, they both seem to be acting fine.

What is going on? I have some Mysis shrimp thawing and I'll try giving them that to see what happens. Any ideas would be greatly appreciated.

Thanks in advance.

 

[Triggerfish]

just to let you know eventually one will try to kill the other.

odd behavior after eating..my bangaii never would eat flakes so no idea on that.

 

[Newreeflady]

Trigger, that's only if they are same sex.

kooken, not sure on that. Are they ingesting air? I always sink my flake food. I don't have banggai (yet) but will soon. . .

GL. I'm interested as to what happens.

-A

 

[Triggerfish]

how to tell them apart?

fellow reefer had two small ones and then after about 2 years they got pretty large and one would not tolerate the other as it was getting bashed to hell..he had to get one out. i took it.

 

[Newreeflady]

Trigger,

He probably had two males. You can't be sure until they either breed or fight I guess. You can do searches, FMarini had some things to say about sexing them (or not.)

Kooken,

How are your fish today?

-A

 

[Triggerman1964]

They are gulping air.Not good at all.Lost a lionfish that way.

 

[Paul B]

The above post is correct. Stop feeding them flake food. They are carnavores and should not eat at the surface. They need fish in their diet.
Paul

 

[kooken]

Thank you all for your posts.

The larger cardinal seems to be doing just fine. He doesn't seem to have a problem with eating Mysis shrimp or krill, so that's what I've been feeding him instead. The little one, sad to say, died a few days after my first post. I am not positive if it was directly related to whatever issue he was having with the flake food, or not.

I do sink the flake food when I put it in the tank, so the fish usually eat at mid-level rather than at the top of the tank.

Thanks again for your help.