Salicylate test measures ammonia levels in both fresh & saltwater aquariums. Ammonia, the #1 killer of tropical fish, is continually produced in the aquarium from fish waste & uneaten fish food. Tests ammonia levels from 0 to 8 ppm.
I would definitely recommend adding these little guys to your tank. They are very playful and entertaining. My three were very healthy and quickly adjusted to my tank.