Just wanted to share some observations as it may be of interest to some.
A few months ago my dozen cardinals were wiped out by - I think - epistylis. Save for three ottos and some amano and cherry shrimp, the tank was left pretty much unoccupied. Last week I picked up 20 cardinals. So this is quite a good but unintentional experiment into how cardinals behave in different sized groups.
When there were only a dozen, they were shy. They would come out into the open but were easily spooked into cover. They never took food from the surface. I remember having to tell visitors that there are fish in there and point out where they were hiding. Presumably two people in the room was too much for them!
Wind it on to the group of 20, which all went in at the same time. They will happily go to the surface for food, they are never spooked by me or visitors. They also started eating immediately. What I really love, is that when the lights dim for dusk (I have a long dusk period, with it ending on a very low setting for a good hour) their behaviour changes. Instead of staying in the open as they do throughout the day, their activity levels massively increase and they begin chasing one another through the plants. It is so cool to watch. I am guessing that they might be jostling for the best spots to spend the night, but I could be wrong. I didn't see this behaviour at all when there were the dozen.
Of course, genetics may play a role in some of the differences in behaviour and I don't know if one batch was wild caught and the other tank bred etc. Though they were from the same shop. But even so, I think it does point to the size of shoal that makes them comfortable. I often see 6 listed as the minimum, but I really think this is far too few.
A few months ago my dozen cardinals were wiped out by - I think - epistylis. Save for three ottos and some amano and cherry shrimp, the tank was left pretty much unoccupied. Last week I picked up 20 cardinals. So this is quite a good but unintentional experiment into how cardinals behave in different sized groups.
When there were only a dozen, they were shy. They would come out into the open but were easily spooked into cover. They never took food from the surface. I remember having to tell visitors that there are fish in there and point out where they were hiding. Presumably two people in the room was too much for them!
Wind it on to the group of 20, which all went in at the same time. They will happily go to the surface for food, they are never spooked by me or visitors. They also started eating immediately. What I really love, is that when the lights dim for dusk (I have a long dusk period, with it ending on a very low setting for a good hour) their behaviour changes. Instead of staying in the open as they do throughout the day, their activity levels massively increase and they begin chasing one another through the plants. It is so cool to watch. I am guessing that they might be jostling for the best spots to spend the night, but I could be wrong. I didn't see this behaviour at all when there were the dozen.
Of course, genetics may play a role in some of the differences in behaviour and I don't know if one batch was wild caught and the other tank bred etc. Though they were from the same shop. But even so, I think it does point to the size of shoal that makes them comfortable. I often see 6 listed as the minimum, but I really think this is far too few.
