What they are
Redtails do not breed on their own in aquaria, and neither do hybrids form by accident. The tiger redtail was produced with hormone injections, in an attempt to make a good food fish, and some of those fish end up in shops.
Living with them
Hybrids can share a big tank with adult redtails for years and grow to about the same size, three and a half feet or more. They are not gentler: a big hybrid can be the bully of the tank. Feed and keep them exactly like a redtail, including the vitamin B1 care.