Sick again or aggression issue?

[dsun]

I adopted a 4.5'' red shoulder from my fathers tank. He was out growing the tank and I thought it be a good idea to introduce him to mine as I had a hyper dominate ruby. Well now this big boy is boss and hes not that much better than the Ruby. All my other cicihlids are between 2 to 3.5 inches long, and I have a runt who is 1.5''. I noticed that they are hanging out on 1/4 on the left side of the tank while the red shoulder dominates the rest 3/4 right side.

On the second day I had the red shoulder I saw him pooping solid grey/white poo, i probably should have isolated him but he looked healthy and fine in my dads tank.
Yesterday i noticed the runt had some nipped fins and he poop white stringy poo...today hes pooping normal brown but now my OB just pooped white stringy poo. Does this mean they are too stressed from being bullied? They accept food just fine and is acting normal. I dont see the red chasing the little guy, mostly the ruby..maybe it was a one time nip.

 

[dsun]

update:

noticed the red shoulder and ruby both pooped semi stringy poop. The front is white while the body is food colored...it hangs from their butt for awhile before falling off.
I vacummed the substrate real quick to remove the crap...hopefully it helps.
Anyone else see this before? on and off white stringy poo

 

[rmiller]

You likely have an internal parasite. You will want to medicate as soon as possible using something like paraguard.

 

[dsun]

could they be constipated? I remember i fed a bit more than normal amount of cichlid chrisps on sunday...i was like whoa maybe i put too much in. Im gonna fast them for 2-3 days. The ones have been doing on and off white/brown poop so im guessing thats better than stricktly white poo