Light on a indoor breeding tub?

[SnailPocalypse]

I have had my new breeding tub set up in my room now for 2 months or so.Just moved some Guppy babies in.My only worry is that I don't put light on it and the only real light it gets is from the kinda far window and the tank that is above it.So you can see the bottom but its dim.I just wanna make sure that the fish will be ok with this.As I can't really afford a light for a breeding tub.