Bosemani rainbows are the most common rainbowfish in pet stores, but if you can get them from a reputable breeder, you'll be happy you did because they will be far more colorful. Also, one of the three pictures here is of a Melanotaenia trifasciata (looks like it may not be a pure location because it is not very colorful). The bosemanis are the ones that are half orange and half blue. Females look very different though!
Also, be advised that the size listed in the profile is wrong. Adult males will often reach lengths of 15 cm, and since these are active schooling fish, they should be kept in a group of at least 5 individuals in a tank that is at the very least, 4 ft long and 55 gallons, although an even larger tank is preferable. Could someone please delete the picture of the trifasciata, or move it to the correct profile?
I've found these fish to be amazing. They have similarly tenacious personality to pacus when feeding. I briefly tried a school of 6 in a 40 gallon African tank, far to small. But if you had a tank 6 ft or longer you could keep a cloud of these with more aggressive fish. Very durable and colorful I highly recommend them. They do well in community setups as well. Be sure to have an adequately large tank with adequate current and you'll really enjoy them.
Boesemani Rainbowfish are absolutely wonderful. I had three of these at one time in a 38g. They would occasionally go at each other but never after other types of fish (corys and giant danios). When it got down to just one, he took part in the school of danios wonderfully. They would all circle the Boesemani when afraid and follow his lead. Early in the morning mine were/are dark blue throughout the center, before the tank light comes on, and there is only sunlight starting. When unsure of things they will get a blue stripe running horizontally down their body. As someone else stated, the size is incorrect. My last one is easily 4in/10cm.
For the people in this thread asking about keeping these guys in smallish tanks (or claiming that it is ok) please reconsider. These fish can reach 5.5" over time and are big swimmers. You can make it work in a 55 depending on your other stock, but 75 would be my recommendation at minimum (same length as 55 but more room to turn around). If you're claiming your fish didn't hit the 4.5-5" range and citing that as an example of when it was fine to have a smaller tank, I'd urge you to consider why your fish did not reach that size. Just some friendly advice from a guy with a 90G rainbow tank that already seems a bit cramped :)
It is a great fish to have in a planted tank. I have a group of 5 males and 6 females. They are really lively and wonderful. However they can prey on smaller fish like Neon tetras, as i discovered the hard way. So if you want to keep smaller tetras in your planted tank, these may not be the best choice.
I have a group of 8 of these, 3 males and 5 females, in a 75 gallon tank and I'm not that much of a fan of these fish. I purchased them because of their beautiful coloration and schooling behavior, but I have been disappointed with both. I purchased some from a breeder, so their colors are much better than what I have seen in petco, but unless they are stressed the males really do not get very dark and the females are fairly bland. My fish also do not school, they kind of each do their own thing and their behavior is rather uninteresting. I would not purchase them again. They can only eat very small food because their throats are very small, but despite that they will chase and bug my RCS and Celestial Pearl Danios.