Three feet tank? How many gallons is that? My tank is 3 feet across and its only 46 gallons.
Clown loaches get to be about a foot long. 6 of them are going to need something over 100 gallons to keep them happy. Even one of them would need at least a 75 gallon tank. Silver sharks get to be about 14" each... Tiger Barbs should be kept in groups of eight or more to keep them from getting too agressive... Guppies should not be kept in with any of the afore mentioned fish. They are likely to get eaten. Everyone but the guppies are classified as semi-aggressive because they will go after smaller fish.
This tank may work for now, but it wont last much longer. Fish wont grow to the size of their tank; they'll just die before they reach maturity.
Fish deserve time, effort and lots of care!!! Please don't impulse buy!
55 gallon, 46 gallon, 10 gallon, 5 gallon, 2.5 gallon