A 2-footer is likely to be either 60 ltrs (15 US gallons) or 70 ltrs (19 gals). Several of the fish you mentioned (pleco, clown loaches) are not at all suitable for such a small tank. Also, I suspect you added them in one go, or quite soon after each other, which means the bacteria colony in the tank did not have time to mature enough to deal with their waste. They will have died of ammonia poisoning. And several of the fish mentioned are not hardy enough to go in a new tank.
How many fish do you now have? How many platys? Mollies?
You need to read up on cycling a tank (pinned topic).
You also need to buy a test kit that tests for ammonia, nitrites and nitrates (liquid tests are best). If either ammonia or nitrites are over 0.5 ppm, you need to perform a partial water change (replacing with dechlorinated water!). You may need to do this everyday until the levels stabilise. Change, say 33% the first day, then 10-20% a day.
Despite the dead fish, you are probably still overstocked. To give an idea, a tank like yours is big enough to sustain a population of about 3 mollies and 3-4 platys. Unfortunately, khuulie loaches are schooling fish, so he would have been happier in a group- but you won't have room for that. The plec is a heavy waste producer and some plecs grow LARGE. They also have special dietary needs, so you need to know what you've got. What kind is the loach?
As you can see, there is a lot of research to be done here.
Hello all hope you can help feeling very confused had tank set up for probably 2 months and am losing couple of fish per week don't know what l am doing wrong especially seeing as l have four new baby fish and they are doing well any advice would be greatly appreciated
