The second photo is my favourite 5 pieces Harlequin Rasbora. I bought them because of their luminous orangy color. Ever since I kept them in my shrimp tank, they managed to eradicate the population of seed shrimps and tiny white worms. I hardly noticed any pesky planaria too. However, they do harm tiny shrimplets that swam (float) carelessly in open area unless those shrimplets hide in bushy mosses or walked next to the adult shrimps until they are big enough to appear alone before their shy prey. Any shrimplet that is bigger than its mouth will be spared as meal. As such, it is not advisable to keep too many of them even though aquarium hobbyist think 10 is an ideal number.
The top photo shows another type of dwarf Rasbora that loves to swim in group too. They are small and, unlike the Harlequin Rasbora, harmless to my shrimplets. If I have more spaces, I will definitely keep more of this fish. They feed on tiny tetra bits (sometime a little powdery form) which I fed to my shrimps. They do feed on tiny white worms if they spotted them floating around, not that such worms are common in my tank now. Unfortunately, the above fishes were not able to rid the button snails in my tank....hmmm so nobody is perfect in his world.
