Will i need any filter for the following descriptions?

Well, the best way not to kill fishes is changing their water everyday. Fill a tank with water equivalent to the one your aquarium has and leave it on daylight(not direct one, it will catch strange stuff from air, I suggest near a window)for 24 hours. Then remove the water the aquarium has and fill it with the new one. Be sure to be able to refill fast or no fishes anymore! No need for filters etc. For the algaes, you have to use chemicals, there's no other working way. Use chlorine based shock, it's for the same reason but for pools. It works just fine. For the rocks just remove them with full water. This works my fishes live 3-6 months each, satusfying for me. Just remember to feed them with the right amount. Most of my fishes die because of overfeeding them, rarely by not feeding them.