Peaceful/happy Community Tank Fish

Killifish are not peaceful with non-killifish tankmates that's for sure. Unless you get something from the genus panchax

 

What are the tank dimensions?
 
I'm afriad that already you may already have some conflicts in there...
Otos are social and would do far better in a 10+ group
Rubbernose Plecs are specialized fish that need cool (typically 20-23C for the common UK imports), fast flowing (10-20x real turnover) and oxygen rich water from lots of surface rippling... You need this fish IDed, asap
Corydoras should be kept in at least 6+ groups of their own king, ideally 10+
Female Bettas are usually safe with each other, but not in low numbers, a "soreity" should really be 5+ because they do form a "pecking order." They do not appreciate flowing water and need water far warmer than Rubbernose can tolerate on a permanent basis
Dwarf Gourami can be territorial, so a well furnished tank with lots of line-of-sight barriers is preferable. Again, they do not like much water movement.

You better go and tell all the Golden Wonder Panchax around the world that are not behaving properly then.
 
GWP are opportunistic predators, they will eat (or try to eat) anything streamlined.

 

Would definitly not add angels with gourami (and bettas). Those poor gouramis might end up being bullied to death.

 

I should be specific then, a striped pachax (aplocheilus lineatus) would be an exception

 

I should be specific then, a striped pachax (aplocheilus lineatus) would be an exception  


A. lineatus ARE Golden Wonder Panchax!
 
I've seen this first hand, I kept a quartet hareem of GWPs, they will even try to swallow large pieces of commercial food that is blatently too big for them (just like halfbeaks), scaring themselves silly when it gets lodged in their large gaping mouth.
 
But fish that are bulkier than ~1.5cm diameter, they are usually model citizens, completely ignoring them.

 

Wow.. shows to prove how long i've been gone in the fishkeeping hobby. I need to be updated with renamed fishes lol.

I've never kept them big enough for me to witness such atrocity but i've kept them long enough to see that they are model tankmates. I have my own no, no list for community tanks since i've tried putting every fish together in the past. Too bad internet browsers were still netscape then and cameras with films are a thing lol

P.s.

I googled the panchax pics and omg, mine was not the plain gold color. Mine was more of a striped and cream color lol

 

Like everyone said, you're almost if not, up the stocking limit. How bout you get another cory so you can have a trio? Wouldn't hurt in my opinion

 

Actually it's best to have a group of 6+ all of the same species. If there are individualls, they'll unwillingly join the gang for safety, but it's not something they prefer to do. Perhaps move the ottos to another tank and stock up on more cories?