Name: Dermogenys pusilla
Origin: Southeast Asia
I've had 5 of these fascinating livebearer fish for about 6 months now. As is evident from the above picture, they have a longer immobile lower beak and a smaller mobile upper beak (hence the name). I have them in a 150 L brackish water tank with other livebearers like mollies. They are very skittish in the beginning, but eventually settle down and are real beauties to watch. They behave like miniature barracudas and even feed like one. They take flake food readily, love live tubifex worms and small insects like ants. They have a tiny mouth, so I would recommend breaking up flakes or feeding them micropellets. They like to swim around on the surface and need to be provided with more surface area than depth. Also they tend to be a constantly squabbling bunch, so give them some floating plant cover for the smaller ones to hide. When you buy them make sure their lower beak isn't broken or the fish will most definitely die within a few days. Being surface feeders, try to feed them in different spots where they may face less competition from other live bearers. Once they recognise the owner, they will stop being skittish and will actively gather near your fingers while feeding. A very peaceful fish that should not be kept with any other aggressive fish as they will succumb to fin nipping.
These are great little surface dwellers. I had 5 Dermogenys pusilla pusilla. They will happily take crushed up flakes and any live food. They sometime crash the beak-like mouths against objects and cause it to break. The males had disputes, but their conflict never resulted in any harm and they are very peaceful to other fishes.
Very hardy fish, that almost never leaves the surface. It's a pleasure having the halfbeak in the tank. I think it is disease-resistant. Eats anything that floats. prefers a mild, steady current. No conflicts whatsoever with other fishes, very peaceful and minds its own business.
I found some of these at my local pet store and was told that they are not very hardy and that they only eat live food. So far it has been 2 months and it is still alive and loves everything I feed him. You can't see him when you look from far, because he is small and stays at the surface of the water, but he is great to watch. My angel fish don't even bug him. He plays with little bits of dead leaves, pushing them around. Then swims off to the curent from the filter. He is always the first to eat. I am going to get a few more.
Be careful, these fish can be serious fin nippers and fish chasers. I would not recommend this fish for a community aquarium. I once had 3 individuals in one of my aquariums and they would chase down fish and shreaded a guppy. I noticed that the males were the most aggressive and did most of the damage. These fish hang around the top of the tank and will eat pretty much anything and love brine shrimp. My fish did fine with tiger barbs.
Nice little fish. There is another one that is gold in colour, which is readily available in Singapore/Asia. Don't frigthen them too much, especially if you just introduced them to a new tank, because they rather often will dash into the glass and get their nose bent. If the long nose is bent, it will grow up bent and even get worse. I do not notice that they fight with other fish or among themselves. But quite nice to watch them because they are normally at the top level of the tank and will come to eat the fastest.