There are quite a lot of options with loaches for this size tank You have Zebra, Zodiac, Dwarf Chain, Rosy Loaches but you could also look at Wood Catfish like Oil Catfish or any of the Tatia cats
Yes they would, predatory fish lol, I have underestimated those fish once and that was once too many when customer caught the galaxy tatia eating their Blue Phantom plec that was the same size as it nearly >.<