No, I don't think so. There are some aquatic/marine type paints, used for painting boats, but I don't know much about them. If you did paint it, you'd need to let the paint cure out of the water, and then apply a fish-safe sealer.

Hi
have used acrylic latex paint both in aquariums and ponds with no problems. Is the tub plastic ? If so there is the problem of expansion which causes the paint to chip
They make arylics specificly for them such as Krylon fusion There are also two part epoxy paints made for underwater use and marine applications but I find that plain old acrylic latex works almost as well at about a third the cost. gary

Thanks for your answers, I think I'll play it safe and find a tub with a dark color. I'm just using it as a pre filter on my pump to keep out large particles and my baby fish