I slice mine like cucumber, to give good surface area and put in raw, in a clip. it does not rot down quickly like cucmber so can leave in tank for a few days. my adults eat it fairly fresh and the fry eat a day or two later after it has softened a tad.
the large baryancistrus snowball eat have bigger chunks and eat it raw immediately! they love it. my royal eats it at night and you see all the orange poo in the morning!