In general Aruba is sitting on a shallow sand shelf ideal for confined water classes and spotting rays. Getting out to the coral formations is usually by boat with short rides and you can hope to see the usual Caribbean fishes of moray eels, stingrays, barracudas and yellow tail snapper.
If you fancy going PADI pro then Aruba Red Sail Sports is the company to check out.
Hows the water ?
Water temperature ranges from about 75 to 80 degrees Fahrenheit. Visibility is usually very good in Aruba. Visibility up to 100 feet is not unusual in Aruba.
Aruba lacks walls if anything otherwise there are a great variety of reefs and the speciality is probably wreck diving.
The nearest Decompression Chamber is in neighbouring Curacao.