Your 7.5 gallon tank is OK for 2 frogs. Use a undergravel filter set at low outflow to minimize water disturbance. Make sure the water is always clean and conditioned (Stress-Coat is highly recommended) and do 25% water changes weekly, make sure the new water is the same temperature as the tank water. Since these are aquatic frogs, you need to monitor water quality carefully (pH 6.8, a little acidic). The temperature should be 77(F) or 25(C) during the day and a little cooler at night. You can feed them a variety of worms - bloodworms, tubifex, or chopped earthworms (fresh or frozen, but never freeze-dried). Occasionally, they can take sinking pellets. Feed every 48 hours. They are bottom feeders. You can use aquarium fluorescent lighting with a 12 hours on/12 hours off cycle. Provide hiding places and plants. I would not recommend adding fish, although a betta or a small catfish might be compatible. They are hardy frogs and should live about 5 years.