lost color

First time poster... I have nice little tank 20 gal. (75 liters) with 6 Tiger Barbs, 2 snails and one of those plecos that you never see, never grows (he is probably 6-7 cm)... anyway, I recently noticed that one of my Tiger Barbs turned really pale, almost grayish / yellowish... it's difficult...

Hello all, I hope this reaches someone soon. I have had these red parrot fish for almost six years. Today I noticed that they swam to the top of the tank, started to loose their color, and are swimming erratically. I've never seen them have all these symptoms in one, and I am very confused and...