My Black Tetras are usually the first fish to snap up a meal. And believe me: they really rip into food. My five tetras are the only fish among my zebras and Gouramis that will swim in a steady school. They are peaceful, longlived, well most are peaceful community fish. My friend had some that harassed gouramis! I recommend this fish for beginners.
These fish are the hardiest I ever had. I had a case of (I think) fish tuberculosis and all my fish were wiped out except these, who had all the symptons (wasting away of the stomach region and can no longer eat) but managed to make full recovery.
My friend, who started me into this hobby, gave me two of these Blackskirt Tetras, and I still have one who survived my newbie phase. That's been over a year now! I've since gotten a littler long-fin Black Phantom to keep her company, and plan to get a couple more at least when I get a larger tank for my community. My husband and I were really surprised with how they flip the water surface at feeding time - looking more like little porpoises! And yes, they CAN jump out of the tank when you turn your back during water changes! They're really fun to watch!
I have read all messages, but they do not sound like my black tetras. I have 8 - 3 long fins and 5 short fins. They get along well with each other but any other fish can not be put in the tank. They have attacked and killed a total of 6 other tropical fish that I have introduced to the tank and 1 bottom feeder and have picked them clean. I feed them twice a day and have a 75 liter, and at times they have jumped up out the tank at my hand to grab the food, they act like piranhas.
I have 5 of them and they are very friendly to others of their kind, and sometimes school with my balas. These fish live very long. I've had two of mine for 7 years. Two of them are short fin variety and the other two are long fin variety. I would recommend these fish to anyone.
I had five of these fish when I first set up my 150 cm community aquarium. All the information I read about the black widow tetra (that is what they are called here in Australia) said that it is a peaceful, shoaling fish, which is why I got some. Well, the group I had rarely shoaled and were certainly not the most peaceful fish. They each developed their own territory in the tank and were constantly chasing each other away. On three separate occasions I found a Black Widow with a nasty wound on its face; one lost its whole bottom jaw, which got infected and infected the whole tank. I found them to be overly pugnacious, and the risk for infection due to them wounding each other was not one I was willing to take (again!). Consequently I gave the fish away. On the positive side, these fish are easy to feed and do grow quite big for a tetra. They are entertaining to watch and never bothered any of the other species of fish (only each other). If you have some, just monitor them for injuries.