Cardinal tetra behavior

[aquaglory]

I just added some cardinal tetras to my newly cycled 36 gallon tank (3 yesterday, of which one didn't make it, and two more today-- for a total of four). I would have gotten a total of 5, but I got the last two from the store, today.

Today, before I added the 2 more cardinals, I noticed that the male was aggressively "attacking" the female. The female would run away, then sometimes go back to try to school with the male. Sometime, I noticed the female hiding in the opposite corner of the tank. The male also seems to be eating a bit whereas the female less so. I tried giving them a tiny bit of crushed Spirulina flakes and at a different time 2 or 3 FD tubifex worms, but I get the impression they don't even know that its there. Anybody know if the male was being aggressive or if this is mating behavior? I wouldn't expect mating behavior, normally, given the fact that cardinals are usually difficult to breed and also given the fact that they were just placed in a new tank.

Later today when I added the 2 more cardinals, I noticed that the female from yesterday was being aggressive towards the new female, almost as if to shoo her from the school. In the store, I noticed that the male in their tank was displaying to the female there.

General note: according to PetSmart, these are tank bred cardinals. Also all of these cardinals are from the same batch and were previously together at the store. They had been there for about 2 weeks before I got them.

Water parameters:
Ammonia 0, Nitrite 0, Nitrate 10 (before I added more Amquel plus and did a mini 1.5 gallon water change), hardness 300 (or a bit more based on the paper test strip at PetSmart), pH 6.8. All the tests other than the hardness were using the API liquid tests. The PetSmart water is very similar to mine, but with Nitrate around 15 and pH at 7.

My tank has a good amount of driftwood and has some myriophyllum, Ludwigia repens, banana plant, Java fern, an Anubias, 2 kinds of cryptocoryne, and some struggling baby tears (HC).

I hope someone can help me out with this behavior. Also any suggestions on how to get the cardinals to eat would be greatly appreciated. I noticed them "tasting" some of the micro white worms (I think Carl called them detritus worms), but I haven't seen them actually eating them.

Thanks in advance!

[Carl]

I have found that Cardinals (& many other Tetras can get a bit "nippy" in small groups, which IMO is simply the establishment of a "pecking order", not mating.
Adding more to this school or even other fish should slow this behavior.

As for eating, consider some frozen Brine Shrimp or a more palatable food designed in particular for finicky small fish such as Cardinals; my favorite for this would be the Hikari Micro Wafers

Carl

[aquaglory]

Thanks again, Carl.

They seem to be calming down, already, though the original male still picks the most. As for the food, I saw some of them start to eat the Spirulina, today. So maybe it's just an adjustment phase... I hope. I'll give it another week before I break down and try other foods. At PetSmart, they were telling me that the cardinals were eating their Omega food very well.

[Carl]

I am glad to read the Cardinals are adjusting to the Spirulina (this is one of the better diets, but not as palatable so it often takes more time for fish to adjust to)

BTW, Omega makes excellent foods IMO should you try these.

Carl

[aquaglory]

Thanks Carl.

They are starting to get a taste for the Spirulina, I think. I also think they had been keeping plump on the detritus worms, which are not much harder to come by. I do see them picking at the glass and the driftwood every once in a while. I'm barely feeding them at the moment (one 0.5cm x 1cm flake crushed to fine bite sizes per day, maybe twice). I do have some Omega flakes for bettas, but I'm trying to get the Cardinals to accept the Spirulina, first, before I try the other flakes.

[aquaglory]

A little update: I added 3 more Cardinals and they are now schooling a bit more. The picking amongs themselves still goes on a bit from time to time. At least a few of them are now accepting the bite-sized Spirulina. I think they just were not familiar with it. They are still feasting on the detritus worms, too!

[Carl]

Sept 13, 2010 11:15:49 GMT -5 aquaglory said:

A little update: I added 3 more Cardinals and they are now schooling a bit more. The picking amongs themselves still goes on a bit from time to time. At least a few of them are now accepting the bite-sized Spirulina. I think they just were not familiar with it. They are still feasting on the detritus worms, too!

I have found that most omnivorous fish will eventually accept Spirulina Flakes, it just takes more time then many other foods (that are often of lesser food quality)

Carl