Stick to the veg shown on the sample plate in this thread ..
Recommendations For A Balanced General Guinea Pig Diet
The plate contains: 1 slice of pepper, 1 sprig of coriander/cilantro, one chunk of celery, 1 slice of spring greens, 1 green bean, (optional) one leaf of gem lettuce.
This plate here is aiming for a mix of vitamin C rich veg (like pepper, but there are alternatives if your piggy doesn't like them), 1 herb that is rich in minerals and trace elements (which can vary; cilantro/coriander is the mildest and can be fed most often), 1 slice of a cabbage type veg for magnesium and vitamin C (spring greens is again the mildest and most suited for a daily diet, as it is not as high in calcium as other cabbages and brassicas), and some 'green stuff' in the bowl. The leaf of salad can be varied with something else that you don't feed daily.
The plate is pretty much the mainstay of what I feed my own guinea pigs, with seasonal changes and the occasional special treat to keep things interesting.
For bladder problem guinea pigs, you can feed this mix safely, just minus the lettuce and without any variations; this also works for diabetic guinea pigs (together with grain-free or very little pellets).
Veg that can be feed daily
A slice of Red/Green/Orange/Yellow bell or sweet pepper colour
Couple of chunks of Celery
1 chunk Cucumber
Coriander - a couple of sprigs
1" strip of spring green / cabbage
