A natural swimming pool will attract some wildlife, but moving, aerated water is much less likely to attract snakes or mosquitos. Snakes may pass by, but will be looking for a much steadier supply of food than your pool can provide. Mosquitos will be much less likely to lay eggs in water that's constantly moving.
If mosquitos prove to be an issue, try planting natural repellants like citronella, lavender, or rosemary. Make sure that you keep other grasses and plants trimmed back, other than in the regeneration zone. Long grass attracts wildlife and bugs.
