Fish come in many sizes and in many colors. Carp (koi), goldfish, comets, shubunkins are used as ornamental fish.  Koi and Gold fish are the most common used in backyard ponds. Tilapia make for a great farming fish here in Florida. It is very Important to understanding shade and water temp.
Plants are the most important part of any ecosystem.
Plants soften the rocks as well as bring great beauty to the landscape around any feature. Well placed trees help control sun, shade and air flow. The correct plants will help balance a pond, patio or just as decoration around a home, where as improper plants create Big problems. Proper filtration is a must with all our water systems for continued success.
Dragonflies play significant part of Wetland wildlife.
They are also very important in its general ecology.
Butterflies Most adult butterflies found in Florida feed on flower nectar. Some visit a variety of flowers and others seem to prefer a more specialized menu. Butterflies generally are attracted to brightly colored simple flowers that are not too deep and that are wide enough for good perching platforms.
Any shelled reptile can be called a turtle, There are about 270 living species of turtles, which are grouped into families.
Frogs may be found anywhere in the world (excluding Antarctica), although most frogs are found in the tropics. If you're looking for a frog, probably the best time to look is at night with a strong light - when you shine it on the eyes of a frog you'll see a little red flash.
There are a number of snakes in natural Florida varying from water snakes to rattle snakes.  
In 25 years I have only seen one water moccasin and it left us alone while we cleaned the pond in Sarasota Fl... But I have seen Poisonous snake around,  Pygmy rattlers, copperheads out in the wild
the coral snake is often mixed up with a similar looker, and domestic pythons are growing in big numbers and size. 
Black snakes are a big plus and will help keep other snakes away.