OMG THE FISHTANK!!!!!!!!!!!!?

well since your not being very specific i can only offer vague advice but if the tank needs cleaning you need to take the fish out and put them in seperate containers with the same water from the tank so not to shock the fish when you reintroduce them back to the tank and more than likely your dad has some kind of water conditioner to treat the water from the sink and you should follow the instructions on the water conditioning bottle as to how much to add to the water.Also you probably going to have to clean the filtration system which can be a headache depending on the type of system .Honestly I think you should try calling your dad and let him know whats going on so that none of the fish die and he isn't going to be mad at you for being honest and letting him know before things get really out of hand. As for the water level being low I dont think thats really a big deal as long the fish still have enough to swim around in.