I missed my Sunday update on my little guys because I was out of town. Being that I was out of town for a few days I decided I would conduct a little experiment that I unfortunately knew would result in the death of some if not all of my cardinals. So that we all could learn I figured I would post my findings here.
So as of Sunday my first batch was 1 month old and my second batch was 1 week old. My first batch I had my first death on Thursday as a result of aggression. Being that I had them in a small breeder box with 20 cardinal in there I new it was only a batter of time. Unfortunately for these little guys I didn't have time to go to the store to buy another breeder box before my trip. So I figured I would drop half of them in my display tank, which is a low flow system. This tank houses a black & White pair of clowns and also the mother and father cardinals. The father is holding again so I wasn't worried about them and I wasn't too worried about the clowns, I was more worried about the female cardinal. At first I seen no aggression anywhere and sure enough as I was walking out of the house I started to see the female chase down one of the cardinals, so I assumed by the time I got home the rest would have been part of her dinner.
As I suspected I lost all but one (unless the others are in hiding) of the cardinals that I let go in the main tank. As far as the rest that were in the breeder box I lost two more of those. I was gone for 3 days so I'm not sure if it had to do with lack of food or aggression.
As for my 1 week old little guys all 9 made it through the 3 days so far.
So my take from all this, is that one month is not nearly old enough for the display tank and secondly they are never old enough to be with mommy. My second take from this is that 3 days for fish past I would guess about 10 days old with out food is a little too long. Im not sure if I lost them because of aggression or lack of fat/protein, or a combination of both. For fish less then 10 days I would say you are ok for up to 3 days being that they still have a little of their fat reserve from the yolk sack. From my understanding after 10 days is when they really start to need the high fatty foods which is why we start to enrich the brine shrimp as soon as possible.