Some questions for you...
1) Of course how long has your tank been running?
2) What size tank, and what type of filter
3) how are levels
4) What color cloudy is it? Brown? Green?
about 2 months, its got a built in under gravel filter which gets filtered in the lid, but its not the size of the tank abit small,
the water colour is cloudy, its been fine crystal cleart up until a fw days ago
The first thing to do is start doing water changes. Using a siphon, vacuum the gravel and remove about 30% of the water every day until it clears. This will give you some time to analyze the situation and figure out what the problem is so we can help you solve it.
I'm not familiar with your tank. Can you tell me its water capacity in US gallons? It would also help if you could tell us the ammonia, nitrite and nitrate levels. That would give us some clues about what is going on. The temperature is also a helpful thing for us to know.
What do you feed your fish and how often? Overfeeding is often the cause of cloudy water, so it might not be a bad idea to cut back a little until the water clears.
well i cant explain the cloudy water ...But just from reading what u have in your 16 liter for fish...well it seems a bit over stocked...You should only have 1 rainbow shark in your tank as they can become very agressive towards each other...plus your clown loach will grow pretty big...and they should be kept in atleast groups of 3...your silver dollar will outgrow your tank aswell...They might be ok now...but they wont stop growing ....good luck....