Multipunct aggression

[Taratron]

A Lake Tang tank at work, until yesterday, was stocked with 2 multipunctatus synodontis, and several cichlids. When I asked my boss about adding to the multi school, she did not seem overeager, nor too uninterested.

So as luck would have it, I found a breeder in Phoenix here who was selling a trio of WC multis. I snagged them up asap, and yesterday morning, during the lights out of night, added the three fish, all of whom ranged from a half inch to an inch smaller than the older two, to the tank.

Lights went on several hours later (I work elsewhere in the wee morning hours in the zoo), and everything seemed calm. The new arrivals even ate. The peace did not last.

One of the older multis began chasing and even attacking the newcomers, as well as the other older cat! I was told a while ago that our two were a "breeding pair," and had seen this same syno chase the other, but no damage had ever resulted.

Needless to say, an hour later, and after removing nearly 100 pounds of rockwork, I caught the offender and he is currently cooling his whiskers in a bucket with air stones. My question is this: I thought multis were a schooling fish? The other older syno does not mind the newcomers, and does not attack them either. Do I just have a very aggressive multi on my hands...and what to do with a multipunct that is?

[Dinyar]

Rearrange the rockwork and put the offender back in. They may bruise each other initially as dominance is established, but no lasting damage will result.