Something unexpected re: praecox rainbows :(

[fearlessfisch]

Last week I bought a single dwarf neon rainbowfish, because a bout of parasites had left me with only two in the tank. The fish budget is limited this month, so I only bought one new fish, but I figured a school of three would be better than two.

The two older and bigger rainbows have excluded the new fish. They swim together, but when the new little one tries to swim with them, they chase him away! Now he spends most of his time swimming alone.

I didn't think schooling fish would do this. I thought they would automatically want to be with their own kind. I feel so bad for the little guy--I think I am going to have to splurge and get at least one more smaller friend for him. I really didn't think the others would do this.

I am a little mad at them.

 

[joannde]

That happened with my panda cories also, but the 3 bigger ones didn't actually chase him, but I rarely (if ever) see all four togehter. The little guy always seems to be on his own. Since I can't get any new fish until the 5th (ick treatment) these dudes have a bit more time to let the little guy "play in their reindeer games" (sorry - couldn't resist - it just reminds me so much of the story of Rudolph the Red Nosed reindeer). Maybe your two will eventually let him in too.
Are the two remaining a male and female ? I'm just wondering why they'd exclude the newbie .... or maybe like all of us they just need time to get used to a new neighbor

 

[toddnbecka]

I have a school of 10. 1 is from 2 eggs that were on some live plants included w/a cherry shrimp deal a while back. They took weeks to grow large enough to ID, and longer yet until they were big enough to add to the 55 community tank. The larger/older of them immediately joined the rest, but the smaller, moved out of the 10 gallon because the shrimp were breeding, didn't "measure up" to the rest. It disappeared after a few days, most likely eaten by a larger fish.
Are the fish all males? 3m/2f is a good ratio for them, but 2 males may be less inclined to accept another male w/out any females present.

 

[fearlessfisch]

You know what, I think they are all males. Maybe I need to get some females for this group. I didn't even think about the sex when I bought them, but I liked the red coloring on the males better.

Thanks for the input. I bet that is part of the problem.