the most dominant endler in the tank went missing, now one of the other endlers is being bullied and acting weird/sick (he has the shimmies possibly?)

[lavathebetta]

so yesterday i noticed one of my fish was missing, i've been looking everywhere but cannot find him, so he either died and was eaten by the other fish in the tank or he jumped out and my dog ate him. but now one of the other endlers is being bullied by the other frequently when i was feeding, the bullied one ate a little bit but wasn't able to eat much as the other kept chasing him around. before feeding time, he was swimming in place and then all of the sudden twitched/had a seizure of some sort as he kinda thrashed around? it didn't fit having "shimmies" but i noticed what could be a mild form of this behavior after feeding time. his fins are also slightly clamped.

i tested my water, and it's 0 ammonia 0 nitrite and 0 nitrates (which is weird, the tank is cycled but i do have a lot of floaters in there that have been sucking everything up, not to mention i've been doing daily water changes to treat one of my corydoras). the water temp is at around 75F, which i know is a little cold, my heater is not doing its job and i'm trying to get a better one. i've been treating the tank with aquarium salt, pimafix and daily 20% water changes as one of my corydoras had these weird white spots on him, and another started showing signs of fungus. the corydoras have been improving.

but i'm not sure what could be causing that endler to have such weird behavior? could bullying be stressing him out that much? should i try to separate the endlers until i can get more to fix their hierarchy? TIA!

 

[Essjay]

Did the endler sort of curve its body sideways then twitch in one place? That's how a male endler displays to a female - or another male.
I used to have endlers before I knew my water was too soft for them and the males were always doing that.

 

[lavathebetta]

Did the endler sort of curve its body sideways then twitch in one place? That's how a male endler displays to a female - or another male.
I used to have endlers before I knew my water was too soft for them and the males were always doing that.

not really, he just would swim in place for a time and make movements kinda like how a snake slithers (a bit of a rocking back and forth). i did separate the bully and moved him to into a divided section of the tank, and the bullied endler stopped hiding and is more active but still is shimmying a bit.

 

[Colin_T]

If the dominant fish is gone, the other fish will be fighting over top position in the pecking order.

Pictures and video of the fish will help us rule out diseases.

Make sure the pH is above 7.0 and the GH is above 200ppm.