How do I unlock fiber for paintings?

[BCS]

Do I need to break through to a new biome?

[SKull]

Yes. Just find somewhere that doesn't involve digging through a lot of slime.

[Cotaks]

slime/algea domes have them. find a section that leads to the plants without digging into slimlung, then your fine. you can dig past slimelung (a tile with slimelung, you can dig the tile(s) around it) but once you dig up slimelung be prepared to counter it, or start a new game xD

[Miningcheeseman]

Slime lung is very easily countered by spamming deodorizers, my dupes have never caught slimelung when I do this. However using the slime for algae distiller, you'll want an ore scrubber to deal with that. Otherwise so long as you don't plan on using the slime for anything like that, or you're not playing with hyper sensitive immune systems, just deodorizers will turn the infected polluted oxygen before the slime lung has time to grow into anything serious.

[AlexMBrennan]

You can also get reed fibre from dreckos if you prefer dealing with hydrogen & chlorine to dealing with slimelung.

[TheCylon]

You can obtain 1 Reed Fiber from Thimble Reed after two cycle of growing or 2 Reed Fiber can be obtained by shearing a Drecko, after he spent 8 cycle in Hydrogen.
Full reference: https://oni-db.com/details/basicfabric

[neo5apien]

It's probably easier to carefully cut a few hidden objects out of the slime biome than it is to get a ranching system set up to shear dreckos. Should be able to get a handful of seeds that way. Just don't dig up more than a tile or two of slime if you've got a lot of polluted oxygen in your base. Or you can take the time to spam hall of deodorizers next to an airlocked ore scrubber room so you can go to town digging up the whole swamp.

They take polluted water, and are a good way to get rid of germ ridden polluted water from your toilets and sinks or that you've got laying around the base, since nobody's gonna be eating the stuff growing from it. Set your toilets to flush straight into a handful of hydroponic thimble reeds and they'll suck that crap right up, keeping food poisoning germs contained and away from other water supplies.