Would it be O.K. to feed guinea pig mix to tads?

[John]

fish powder because it contained animal material as well? (microinvertebrates probably are fed on as well on the leaves.) What kind of fish powder do you recommend?

I just purchase what ever is cheapest or on special offer at the pet shop - there's not much difference between fish foods - they are mostly just fish meal and things like wheat and corn meal.

What do you think of the Guinea Pig mix itself?

What's in it? If you're talking about a general guinea pig food, those tend to foul the water very quickly.