im assuming by your name this is your first tank so lets start from the beggining
-DON'T ADD MORE FISH
with that said did you cycle your tank, if not look at the sticky cycling your tank. the water could be cloudy because you just filled it but also because there is driftwood. you should soak driftwood in a bucket for a week or more to make sure it doesnt cloud the water. very rarely you add fish to a brand new tank. you already put to many fish in your tank
-never rinse off your filter when your cycling your tank,
it just takes that much longer to cycle. so does doing water changes to your tank. but you no longer have that choice because there are fish in there. do a 30% water change a week to keep the ammonia down. also to keep the nitrItes and nitrAtes down.
-if any of the fish die do not run out and replace them, your just making the fishes enviroment alot worse. even if you mean well. it just makes the fish more stressed out.
sharks are tropical fish. do you have the right equipment to keep tropical fish. airstone, airpump. heater. water
do you have the required testing kits
ammonia
nitrates
nitrites
ph
ect
all these test kits will tell you how your fish are doing. are they on the edge of death or are they thriving and having a happy healthy life.
within the 1rst week ammonia should be your biggest problem. but as time progresses nitrates and nitrites will start to show. all these are lethal to fish. so is to high ph. to cold or to warm water. unless your water paramiters a perfect for your fish 3 things could happen to them
-they could ultimatly die
-they could live a stressfull life and leave them open to dieseses. ick for example is very popular in tropical freshwater aquariums. so on and so on. desieses could take a heavy toll on your fish and even with this option in the end they will most likely die.
im not trying to talk you out of the hobby, on the contrary im just trying to make this a easier and smoother experience for you and the fish.
-with the right water conditions your fish will thrive and so will your plants if you decide to get live plants sooner or later, maybe never. most people are discouraged and quit the hobby because they do not know about the cycling process and all there fish die. when you follow the right rules and keep your aquariums paremiters right this is a very fun hobby.
Fish keeping is a very fun and intertaining hobby to have, but in order to have this hobby you need to have alot of patience, well...most of the patience is to get through the cycling process. but once the cycling process is over its just pure fun. untill cleaning day, even then its worth it. cycling takes at the minimum of a month. don't worry you only have to cycle it once unless you completely take apart the tank.
welcome to the forums, good luck
&
don't forget to have fun