If you can find them, emerald-eye rasboras (R. dorsiocellata) are quite small- but not too small- and are very beautiful fish.
I second the Harlequins. Or Espe's or Hengel's Rasboras.webcricket said:Maybe Harlequin Rasboras, or another small rasbora?
lets try and keep in mind that his BB cats are potential predators and would probably go after harlies IMO.Web Gazelle said:I second the Harlequins. Or Espe's or Hengel's Rasboras.