This tank is a 20 gallon tank that I've had for over a year and the Tiger Barbs in the tanks were some of the first fish I put in this tank. This tank has 4 Tiger Barbs, 3 Gold Barbs, 3 Rosy Barbs, 1 Dwarf Gourami, and 1 Red-Tailed Shark. It has been a relatively healthy tank up until about a...