Ampullaria

Some species of the apple snail can grow to 20 cm in the wild, but those found in an aquarium (belonging to the Ampullaria genus) do not exceed 7 cm. They eat vegetation and detritus, helping to restrict the development of algae, and like fairly hard water. Unlike many other gastropods, they are sexed and lay their eggs outside the water. Size: 6-7 cm.

• Aiptasia
• Planorbis
• Goniopora (Poritidae)
• Entacmaea
• Ceriantharia