I have 5 Rosy's in a 280 L community. Only one has ever displayed the rosy color from which I assume they get their name. They are the most voracious fish I've had, other than my angelica cat. These guys go nuts at feeding time. In fact, if I approach the tank they get so excited that they almost leap from the surface. They aren't my favorite fish - they are just too aggressive at feeding time, chasing others away. They also pick on my snails for some reason - all 5 ganging up and picking on it. I've had good luck keeping them alive and healthy.
I started a small 30 L tank for my little nephew nearly 4 years ago. Five months into the tank, I bought him 2 Rosies to add to the tank. They proceeded to eat all the other fish and a snail. A few weeks after the snail I awoke to find only one Rosy left. I immediately assumed that the other had jumped from the tank. After a few minutes of searching I came to the realization that one had eaten the other. It has now been about 3-1/2 years and Dennis (my nephew named him) is alone, 10 cm, fat, and rosey. The secret to this tank (we never check the pH) is to add Zephyerhills bottled spring water when water level drops. Amazing but true.
I have 2 long finned Rosy barbs in my 40 litre tank with 2 golden neon barbs and a few danios. I've discovered that the more barbs you have the better, since when there are only one or two of them they start fin-nipping the other fish and fight for dominance in the tank. Once there are more than 3 they are fine and happily move around in a school. The long finned are the prettiest fish and fill up the bottom of the tank, which is handy since the danios usually stay up the top. Only real problem with them is they love eating my plants and so far my amazon sword is the only thing they haven't been able to chew through!
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