Hi and welcome to the forum
The 2 silver fish are mollies that do best in water with a pH above 7.0 and a GH (general hardness) above 250ppm.
The blue fish is a dwarf gourami and they come from water with a pH below 7.0 and a GH below 150ppm.
The GH (general hardness), KH (carbonate hardness) and pH of your water supply can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).
Depending on what the GH of your water is, will determine what fish you should keep.
Angelfish, most tetras, barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.
Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.
If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.
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The tank water is milky cloudy and this is usually caused by uneaten food and a filter that is not fully established. If the filter media/ material was replaced when you cleaned the tank, then you will be doing a fish in cycle. This is where the fish are in the aquarium while the filter develops the good bacteria needed to keep the water clean.
During this time you should reduce feeding to 2-3 times a week. Don't worry, the fish won't starve. And do a 75% water change and gravel clean the substrate 4-8 hours after feeding. You should also get a test kit and monitor the ammonia and nitrite levels and do a 75% water change any day you have an ammonia or nitrite reading above 0ppm.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
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If you post a picture of the filter and any detail about it, we can tell you how to clean it without removing the good bacteria.