So in my 90 G i have a 4" senegal bichir and its time for me to get another fish, should i go for an african butterfly fish or a needle nose gar, or some other species of gar?
Both are top dwelling predators so they would both be good options. The needle nose is actually a false gar but is still neat nonetheless. I wouldn't do any actual species of gar in that tank unless you have bigger tanks you can use, because they will all outgrow a 90.