are archer fish more hardy then cichla?

[kendragon]

Do you have aeration like an air stone in there? Could be that when the cichla got bigger more air was needed. Just trying to help you figure it out. Don't give up bro.

 

[WckedMidas]

nah no airstone. but the water runs down the back of the waterfall
this is how two of the filters return hoses are one on the end other on the side meeting in the corners . I figured the ditrubance would make some o2

and the falls

 

[WckedMidas]

realy figured the water runing down the waterfalls would make o2 more then plenty

 

[WckedMidas]

anyone else got any ideas on what might be causing this or a way to prevent it?