A YM2610 takes 19qts.
If you do a search in section, the ideal fluid to use is John Deere Hy-Gard J20C. Both Yanmar and Deere developed this fluid for our compact machines. Yanmar calls their product TF500A. Make sure it has the A.
With all that said, You can also use TSC's Premium UTTO fluid because on the jugs it states, meets J20C. Blain's Farm and Fleet states, meets J20C requirements. Do not use any fluid that says, compatible. You can see all the class-action lawsuits with those on the web. Many of them are recent.
If you have a loader (FEL) and/or Power Beyond and/or SVC (selective valve control) for the hydraulics, expect to use even more in the machine.