Plastic tubs for fish?

[chesterthehero]

i use them as qtanks... the colors on my fish always get very very washed out after about 5 hours.. and they never get their color back while in the tub... however they are often the only thing in the tub so that (plus general stress) may be why.. they usuially get their color back in 12-48 hours once they go into a normal tank