Help locating proper adapter

[kth132]

I'm not really sure what this would exactly be called trying to do some online searching to see if I can order one this came off my Red Sea manifold I need to keep the threaded piece the same size but I need to go down a size smaller on the nipple part for my reactor

 

[Saltyreef]

Thats a barbed fitting :)
Here you go.

https://www.bulkreefsupply.com/pumps-plumbing/plumbing/barbed-plumbing-fittings.html

 

[kth132]

Thank you figured out the right terminology after asking a few people