Psycho Tetras, killing other fish

[Brooklyn]

OK, I've been having problems with my new 29g tank because the fish I moved into it from my old 10g (which now houses a crowntail betta) are attacking any other schooling fish I put in with them.

My tanks:

29g
2 red eyed tetras (about 3in. long)
1 high fin tetra (3in.)
1 algae eater
1 female betta

10g
1 crowntail betta

The tetras don't mess with the bettas (I had the male in there for a short time...I didn't realize he would attack the female) but when I added 4 guppies they began to shred them. I did save them all, but I am quite puzzled at why the tetras became aggressive. The same thing happened when I put "younger/smaller" tetras in with them. Again, I saved the poor newbies before the were seriously injured. I'm just very confused now.

Is it a size thing? Do I just need to get a larger breed of schoolers???
Advise please

Brooklyn

 

[hurricanejedi]

I'm not sure but if they are like usual tetras they would prefer a school. Maybe the aggressiveness is comign out because they are not confidant in their surroundings. I'd say 6 usually is a good school size.

But I'm not familiar with your type of fish so not the most knowledgable.

 

[anonapersona]

New tank?

New? as in "might be cycling" new?

Test for ammonia. Change water as much as needed to get ammonia below 1.0, even changing water several times a day is OK, 30% to 50% water changes as needed.

Move decorations from the old tank to the new tank to help transfer bacteria. Also try to get some filter media from the old tank into the filter of the new tank, cut a bit of sponge or something.

 

[Brooklyn]

Thanks! Beautiful cat BTW.

I really didn't want to add any more tetras because I was wanting to go more in the cichlid direction. I'll think about it though

Brooklyn