Identifying specific species of Apple Snail can be very difficult and since several species are commonly sold in the trade, this page applies to Apple Snails in general, rather than a specific species.
Apple snails are a tropical snail species which can be kept succesfully in most aquariums with small peaceful fish. Unlike 'pest' snail species, Apple Snails are unlikely to breed rapidly and overcome the aquarium. The snails will feed mostly on algae and sinking fish foods, and the diet can be supplimented with vegetable matter. Although larger snails will damage delicate plant species they can usually be kept with hardy plants without difficulty. Although a good algae eater, Apple Snails are not the best option for keeping an aquarium free from algae, and algae eating fish will often do a better job. The aquarium should contain hiding spots, air space above water, and a well-fitted lid to prevent the snails escaping.
Be careful when using chemicals in the aquarium since snails are very sensitive to heavy metals and chemicals, especially copper-based products.
Eventual sizes of Apple snails depends on species and can be anywhere between 5-15cm in diameter. Most Apple Snails under normal aquarium conditions will live for 1-2 years, although some can live considerably longer.
Breeding:
Apple snails, unlike many snail species, have definate male and female sexes, so two snails are required for reproduction although females can store sperm for several months. Most species lay eggs above the waters surface and appear as a hard clutch varying in colour. The eggs will hatch after 2-4 weeks.

Paddock Farm - County Durham
Aquahouse - Oxfordshire
Surrey Aquatics & Reptiles - Surrey
Riverside Aquatics & Crafts - Hereford Worcester
The Giant Pet Store - Norfolk
The Aquatic Habitat - Gloucestershire
Woodford Aquatics - Greater London
Fishey Business Eastbourne - East Sussex
Fishey Business Portslade - East Sussex
Aquatic Finatic - North Yorkshire