get a 1.25" threaded coupling x 1.25" slip on the other end and use reducer bushings to your needs..reducer bushing with 1.25 slip on the outside and 3/4 female threads on the inside of bushing then get a barb fitting to you likings..Lowes has all you need in the small pvc pipe fitting isle..
Also try sprinkler fittings. Don't know if you have a Menards out there but maybe you can find at Home Depot
* or look in the sharkbite plumbing fittings for plastic barb adapters at HD
I didnt think the male threads were garden hose type. But hope it it works for you