Hello,
You can still use your T5 light fixture. I use Colormax bulbs to highlight more of the colors in my fish. If you read some of the bulb descriptions you can find ones that work for what you are trying to achieve. Also the newer LED light fixtures are nice as well. Some are mixed with blues and whites which are nice. There are a few LED fixtures that have dimmers on them as well to help you adjust the lighting to your needs.