This experience was beyond our expectations! We saw a lot of manta rays and many of them were sliding just underneath our board and ourselves!! The manta rays are so huge!
I am five months pregnant and felt very safe. All tours gather on the same spot and the boats are around, so you can go back to the boat at any time! The crew took good care of us and explained us about the experience and the rays.
The water is not cold, but because of the waves and the pregnancy, you can feel seasick.
The only reason the manta rays gather is because of the light that attracts the plankton, and we don't interfere with their feeding or lure them to come close as far as I understood, so I think this is ethical for the animals.
I would definitely recommend doing this, this is the only place in the world that manta rays behave like this! And I recommend this tour because it's short and consise, there is no pointless waiting and you get the same amount of water time as with any tour.