Agree about tank size, a 75 is a puddle compared with the water volume where many of the fish you list live.
And could you give break down of your tap water parameters?
Many of these fish are quite sensitive to different water parameter needs.
Elephant nose, and African great lakes species such as Lake Tanganyka spiny eels prefer very hard, high pH water (pH of 8 or above) to remain healthy.
Certain South America riverine species (Amazonian knife fish) prefer soft, low pH (7 or below),
Bichirs originating in Lake Tuurkana, of brackish morays appreciate saline conditions, those S American species would not.