I raised 8 of these L204 and I never did become very good at sexing even large adults. I eventually traded all mine for other species, Subdominant males are very hard for me to tell from the females. heck, i have trouble sexing all but the most obvious males.
I think a sexed trio just may spawn in only a 20 long but they do get to be pretty large as older adults so I probably wouldn't try breeding them in anything smaller than a 40 gal breeder style tank.
They do eat a large amount of wood and produce a corresponding amount of bulky saw dust.
They are also quite omnivorous but they will also keep the side panels algae free. This is helpful because you can more easily see all the debris they produce

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They do like earth worm sticks but I would use more Spirulina sticks and supplement their diet with frozen blood worms.
Once they were well acclimated, mine seemed durable and hardy but I sold some of my adults to friends with little experience with L-number plecos and i felt their tanks were adequate but between the 2 friends, they lost all 5 within a few months after I had had them for a couple of years. I don't know what's up with that. I kept what I thought was a trio in a 29H but finally decided i had retained only males. They kept the 29H pretty well trashed with their waste products. Maybe they are best kept by more experience pleco people?
I found the adults to be more difficult to sex than Hypancistrus and Peckoltia species
So I consider the L204 a handsome species that is above average in difficulty rating them as breeding projects. Large tanks may be the best way to set up your breeders. I don't know all the answers or i would have bred them. i kept mine in tanks with plenty of caves and wood with strong power head currents and air powered large sponge filter. My water is natural moderately hard with a pH of 7.4, KH 6 and GH of 7 with a TDS of about 340 ppm. This water should have been satisfactory for breeding them. I kept mine at about 84*F.
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