This one is great if you suck at rollgoal. I found that in most caves with underground ponds in them, you can catch hylian loaches (they are nowhere near the size of the ones Henas place though).
Also at lake hylia, on the way to the tower where auru is, if you bomb a wall you'll find a huge cave. Lanter oil is required, as it is pitch black and there are several bottomless pits. I used 3 bottles of oil and still wasn't able to explore the whole thing. There are fire keese, torch slugs, tektights, and I think some bulblins in the parts I explored. They seemed to get progresivly harder eniemies, so I bettinf there is a darknut or something at the end. Exploring this cave is one of my main goals now that I've beaten
TP a second time (I didn't even find this on my 1st play).