my threadfin rainbow being very aggressive to the other

[karbomb]

i got my new lights set up today! and almost as soon as i did, my rainbows who have been hiding the past few weeks came out front and center. unfortunately one is being very aggressive toward the other, flashing his fins and butting him. the other one wants nothing to do with this violence and tries to avoid the aggressor but to no avail. the aggressor just chases him around and bullys him.
i don't know what to do or why this is happening
help!

[Dave66]

i got my new lights set up today! and almost as soon as i did, my rainbows who have been hiding the past few weeks came out front and center. unfortunately one is being very aggressive toward the other, flashing his fins and butting him. the other one wants nothing to do with this violence and tries to avoid the aggressor but to no avail. the aggressor just chases him around and bullys him.
i don't know what to do or why this is happening
help!

Easy, Bomb. Rainbowfish are schooling fish. Pair or trios will ALWAYS hassle each other, and perhaps other tankmates. Solution is to buy six of them; eight is better, but you'll probably get by with just six. Pairs or trios is unnatural for them, which is why they misbehave. Threadfins are little guys, so eight isn't out of reach if you have a tank at least 20 gallons.

Dave

[karbomb]

i only have a 10 gallon and my tank is full. no other tank.

[Dave66]

i only have a 10 gallon and my tank is full. no other tank.

Then its time to return the rainbowfish, unless you want to watch one kill the other then start picking on tank mates. If your tank wasn't 'full' as you put it, you could've keep six threadfins in a properly maintained and mature 10 gallon.
Info ([Only Registered Users Can See Links.]) on them.

Dave

[karbomb]

i guess i will have to take em back. i'll just get more danios. think they'll be ok till saturday? i have class 9-4 tomarrow and 6-9 today.

[karbomb]

i took em back
got a shrimp and another danio in exchange