Hi Angie,

This plant is a dieffenbachia. These plants are considered poisonousPlants are a great addition to homes and offices, but it’s important to know whether your plants are dangerous to children, pets, or even adults. Some plants contain chemicals such as oxalates, solanine, glycosides, or alkaloid lycorine that may cause vomiting, nausea, diarrhea, swelling and redness of the mouth, throat, and lips, and trouble breathing. Touching parts of certain plants, especially the sap, may cause various skin irritations. The weight and age of the human or pet involved, and the part and amount of plant eaten determine how severe the reaction to the toxins will be. Although plants may be listed as non-toxic, they can still cause individual allergic reactions. If there is any question after a houseplant has been ingested or touched immediately call the Poison Control Center 1-800-222-1222 The Handbook of Poisonous and Injurious Plants [Paperback]is an excellent reference to keep around if you have young children and pets. and should be kept away from pets and children. If fish in an aquarium nibbled on a dieffenbachia they would die.

You can read read more about common houseplants that are poisonous in my book  Don’t Feed Me To Your Cat! A Guide to Poisonous Houseplants

Here are some plants that would work in your aquarium: Java moss, Dwarf Baby Tears, Dwarf hair Grass, Marselea minuta, Amazon sword plant, Java Fern, Anubias nana, Pygmy Chain Sword Plant, Dwarf Sagittarin. Here is a link to a site that sells safe plants for aquariums.

http://amzn.to/2gljwYi