Gerbil food can be offered in a dish or strewn about the cage's bedding, which allows the gerbil to search for his food as he would do in the wild. A tablespoon of store-bought gerbil pellets plus about a teaspoon of fresh vegetables such as lettuces and carrots should be offered daily in separate dishes or locations in the cage. Guinea pigs also need a mixture of food offerings and their food supply should be changed daily. In a shallow dish, offer your guinea pig about an eighth of a cup of store-bought pellets per day. Add to that as much timothy hay as the animal needs. Guinea pigs should also receive a cup of fresh vegetables and fruits per day. Introduce new foods slowly and in small amounts.
If your classroom bird is a seed-eater or a hardbill bird, such as a canary or finch, be prepared to keep it well supplied with food. These small birds have high metabolisms and need a steady supply of store-bought seed as well as additional offerings of lettuces and slices of apples or oranges. The children should change the food supply daily, ensuring throughout the day that food is continuously available. If your classroom bird is a hookbill such as a cockatiel or parakeet, offer it a daily supply of store-bought seed plus pieces of bark, fruits and berries. All birds will leave behind hulls and other remains from their food, so it is imperative that their food is changed daily and fresh seed and other offerings made available.
The pet store where the fish are purchased can provide information about the proper diet for your classroom fish. The rule of thumb, according to The Humane Society, is to "feed your fish only the amount of food he will eat in a minute or two." Have the children offer a pinch of food, sprinkled over the top of the fish tank. If some of this food remains at the end of the day, it should be removed from the water, as it is a possible contaminant. Check with the pet store for appropriate occasional offerings that suit your fish. Bloodworms or small shrimp might be a viable addition to the daily feeding schedule.
Rabbits need feeding daily. Potentially the most costly classroom pet, rabbits require fresh vegetables daily. They also require daily offerings of timothy hay or timothy hay pellets. The uneaten remains of the fresh food offerings will need to be removed each day. You might consider feeding the rabbit at the school day's end and cleaning out the remains first thing each morning, since rabbits are most active around the times of sunrise and sunset. Treats such as pieces of fruit should be offered occasionally as well.