First Fish, Diamond Tetras Are Acting Aggressive. Help!

[lillykinloo]

Hi everyone! I have a 37 gallon Eclipse "show tank." We allowed the tank to run for 24 hours before adding any fish. The pH is at about 7.2. I would eventually like to have at least 2 pearl gouramis, and I read that they prefer densley planted tanks with low lighting. Since this is my first tank, I decided not to go with real plants. Instead, I have a dark gravel substrate and several fake plants "planted" around the tank with an open swimming area in the middle. There is also a floating plant to provide some shelter from the overhead lighting. Additionally, there is a piece of driftwood and a log with holes and caves for fish to hide in. So, that's my setup in a nutshell.

Our local fish store recommended that we try 5-6 tetras or rasboras to get the tank started (after 2 weeks of cycling, he said we can bring in a water sample and possibly begin to add the pearl gouramis). I really liked the sparkle of the diamond tetras, and the person at the fish store said they are peaceful and should go well with the pearl gouramis. So, yesterday, we purchased 5 diamond tetras. We added them to the tank. I think we have 3 males and 2 females (it's a bit difficult for me to tell). Today, I've noticed that two of the males and one female appear to be "fighting." The largest male is chasing one of the females. She tries to swim away and hide (she hides in the plants mostly), but he will not let up. Then, the second largest male comes over, and this is when the fighting starts. The two males chase each other all over the tank and nip at one another. I haven't noticed any fin damage yet. But, when the poor female finally comes out of her hiding place, the largest male will start chasing and nipping at her again. Then, the fighting starts all over. This has gone on all day today. I thought these were supposed to be peaceful community fish! I am concerned because:

1. I'm not sure that these fish are going to be docile enough for the pearl gouramis
2. These guys are really behaving in an aggressive manner, and I'm concerned that they're going to kill each other

What would you recommend? Do you think everything will be ok once they get used to their new surroundings? Or, should I remove the largest, aggressive male and see if I can return him to the fish store? He's really beautiful (the prettiest diamond tetra in the tank), but i don't want to keep him if he's going to cause mayhem in the tank.

Thank you in advance for any advice that you can offer! Cheers!

 

[crazie.eddie]

They maybe fighting to establish dominance. What you can do is to remove the more aggressive one, then rearrange the decor. This will give the rest of the fish a chance to establish their territories. After a week or 2, put the other tetra back. This normally works for more aggressive fish, but I've never really known diamond tetras to be so aggressive to injure each other. More than likely, they will not harm each other anyway.

 

[lillykinloo]

They maybe fighting to establish dominance. What you can do is to remove the more aggressive one, then rearrange the decor. This will give the rest of the fish a chance to establish their territories. After a week or 2, put the other tetra back. This normally works for more aggressive fish, but I've never really known diamond tetras to be so aggressive to injure each other. More than likely, they will not harm each other anyway.

Thanks, crazy.eddie! I would have never thought of this. Today, the largest male is not acting quite as aggressive, but he's still chasing the others all over the tank, so I think I'll try your suggestion. By the way, your 125 gallon tank sounds remarkable!