dwarf gourami are very sensative I lost 5 quickly from a fungal infection to the head
I have the same arcadia as you i believe and the filter is proberbly not good enough for rams or dwarf gorami, I have a betta and a plec in mine and thats how its staying lol, until i move the plec into a 90L tank when hes big enough to stand up for himself.
I would upgrade the filter to the fluval 1+ or 2+ or even the new U series although i haven't used the smaller ones only the U3 but i like it and it has different flow options for deep water mid water and top water.
I know thats not very useful but given u some things to think about,
hollandA