Please Help....fish Getting Eaten

[Scoobyk]

Hi guys, your advice has never let me down, and I've never needed help like I need right now !!

My tank has been established for months, and no huge changes...however, in the last week:
a) Two Cardinals have been EATEN, and 1 has lost an eye, another part of his fin.
b) A Platy has completely disappeared.
c) A black neon has had his tail completely eaten
d) Two Sterbia Cory's have been beaten up (fins badly nipped / eye missing)
e) 1 sailfin molly had a badly damaged mouth, and died, today, my other sailfin has gone.

WHAT THE HECK IS HAPPENING ?

In the tank 240l, I have
Two angels
5 Blue Bothia
5 Sterbia Cory
2 yoyo loaches
5 red eye tetra
5 odessa barbs
5 gold tetra
5 black neons
3 sissor tails
1 mollie
3 cardinals
3 CAEaters

Any thoughts on what's caused one of these fish to become so aggressive.....my thoughts are it's the CAE ???

 

[bae1994]

id be inclined to say the angels however what are your water stats

 

[Scoobyk]

Water stats should be all good, tested 2 days ago, no issues - will test again though.

 

[Scoobyk]

Ok, just tested the water...slightly confused....Amon 0, Nitrite appears to be up, not sure if it's .25 / 1. What's caused that or could it be due to the fish being eaten ? Is the solution to that water changes ?

I still need to work out which fish is being the aggressive one ???

 

[bae1994]

not sure on the nitrate spike but i think the aggresor would be the angel

 

[Davo86]

the Sailfin with damaged mouth? is this mouth rot/cotton mouth?

You have two species which can become very aggressive,
These are the CAE and the blue botia, Both of these species are far too aggressive to be kept with smaller fish like tetras and both

 

[Scoobyk]

I thought the blue bothia were gentle if kept in the right numbers ? We had 1 on his own for months, no issues, got the others a few weeks back, and no trouble until now ?

Nitrite...what would cause this spike ??