Most of the information available about clown loaches is not completely accurate. The best way to find out information about them is to talk to others who have had great success with theirs. It is important to note that loaches do much better when kept in groups of no less than 3, but I’m starting to believe that 5 is more suitable to their normal behavior. Granted clown loaches grow slower than most other fish, but there are numerous aquarists on the internet whose clown loaches have shown growth rates that were thought to only be possible in the wild. From what I have read and heard from others water quality is the single most important factor in clown loach growth. What are your water parameters? What is the water temperature? What is the tank setup like? Do they have enough places to hide? How many other fish are in the aquarium? These can all have an impact as well. I have also been advised to perform multiple daily feedings of various foods. They especially like to eat blood worms. Make sure that they are actually getting to eat their food. Their aquarium should have good current as well as filtration. The amount of filtration will vary depending of the type of filter.