Marine animal behavior can appear threatening to divers who do not understand the purpose behind the behavior. Many sea animals are completely docile but just "look scary," and some animals that appear friendly can actually be quite aggressive. Click through the following pages to learn about some of the animals that divers commonly fear and to discover which are dangerous and which are not. "Dangerous" Fish and Sea Animals
Aquatic life:
• Stoplight Parrotfish Change Colors
• Caribbean Reef Fish Identification
• Jellyfish First Aid
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Here's yet another reason I love diving. . . . This morning, I sat in front of my clients and spit. How many people can say that? They weren't offended; spitting in a mask is just something a diver does to keep his mask from fogging. I love diving because of the adventure of finding unexpected wildlife and the beauty of the underwater world. I love working in diving because I don't have to pretend to be anything more than the slightly uncouth tomboy that I am. 
The ocean is a comfortable 80 degrees Fahrenheit in Mexico where I guide and teach diving. The air, however, is frequently much, much warmer. Divers travel to tropical beaches to experience coral reefs that thrive in warm waters - the hot climate is part of the lure. Yet, many divers forget that the strong sun and high humidity of many dive destinations can quickly dehydrate. Add to this the tendency of many divers to consume above average quantities of margaritas and beer while vacationing, and the potential for dangerous dehydration becomes apparent. 
What do you notice about the design of a regulator second stage? At first glance a diver may notice the size, weight, or color. Perhaps you notice an interesting little knob on the second stage labeled "Dive/Pre-Dive," "On/Off," or "+/-". This switch or knob alters the airflow inside the regulator, making breathing either easier or more difficult. Turning the knob enables and disables something called the Venturi Effect, which regulator designers take advantage of to assist breathing. Click through the following pages to find out how it works, and when you should disable the Venturi Effect.