Hi,
Assuming these are juvenile American Toads, here is the care that I would suggest:
TANK:
20 gallon tank is fine for now. You may want to upgrade to a larger tank when they are adults.
SUBSTRATE:
I recommend a product called Lizard Liner. It is a carpet-like ground covering that is excellent for use with juvenile toads. It is easy to spot clean, and eliminates the possibility of impaction.
TEMPERATURE:
American Toads are not too picky about the temperature. An average temperature between 70-80 is fine.
WATER:
You'll need a shallow water dish for the toads. Fill the dish with just enough water that they can sit in the dish with their heads above water level and make sure they can easily go in and out. It is important to remember to always use either dechlorinated tap water or Spring Water. Also, be sure to clean the bowl thoroughly each day and refill it with fresh water.
LANDSCAPE:
It is important to provide some good hiding spots for your toads. You can probably find some nice artificial hollow logs and rock caves at your local pet store.. they work well with toads. Also, you can add plastic plants, drift wood and decorative rocks. Be creative!
DIET/FEEDING:
It is recommended that you feed your toads a varied diet, along with a vitamin-calcium supplement which can be dusted LIGHTLY onto their food before feeding. Since these toads are juveniles, pinhead crickets and fruitflies are good, appropriately sized food choices. Juveniles should be fed every day. 2-3 pinheads per toad. I would dust their food lightly 3 days a week.
ENVIRONMENT:
Try to provide your toads with a quiet environment and always avoid direct sunlight. Also, be sure not to use any type of sprays around the tank, this can be deadly to your toads.
HANDLING:
Handling should be kept to a minimum. When you must handle your toads, make sure your hands are cleaned before and after handling.
Good luck!