Can you tell the difference between an L-177, and a L-018

I have one or the other, and have had it for 3-4 months, probably longer… L-018 is an omnivore / carnivore and the L-177 is a biofilm / algae fish, at least as to what I find on the www. If that’s the case, I think mine is a 177, as he doesn’t come out when the rest of the fish are eating, and waits until they have picked the driftwood clean … mine is pretty camera shy… can you tell by looking at the picture???
He’s actually lemon yellow… more yellow than the picture indicates… & is about 5 inches long in this zoomed picture ( can’t get close to the tank, without it disappearing under the driftwood )

This is from PlanetCatfish:
https://www.planetcatfish.com/common/species.php?species_id=153

L018 and L177 are the same fish basically. There is a lot of good info re your fish at the above link.

The combination of yellow markings on the dorsal and caudal fin and numerous yellow spots on the body is specific to this species. L081 (not mentioned in the description of B. xanthellus) is a fine spotted colour form with a dark base colour. L177 is a variety with larger spots more obvious in younger specimens and LDA060 is a variety with ill-formed spots or flakes. All are main channel fishes. After the description of the species in 2011, Aqualog added LDA116 and LDA117 both from the river around Sao Felix do Xingu. LDA116 is a paler colour form with faded almost invisible fine spots. Juveniles show a thin dorsal yellow seam and a little more yellow at the edge of the caudal which it keeps into adulthood. LDA117, by contrast, has a lot of yellow in these fins - about one-third yellow in the dorsal and the caudal fin is about half yellow. The spots are medium-sized and dense. However, adults lose all bright yellow spots and seams with the spots fading to small indistinct marks.

Click to expand...

@TwoTankAmin … thanks, planet catfish, and seriously fish, are my “go to’s” for info… I had been to that link before, but chased down some of the other links from that one… so I learned something… I’m guessing it’s an L-177, as mentioned in my above post….
I had a blue phantom in that tank as well ( about the same size ) and didn’t notice any aggression, but the blue ended up dying, which was unexpected, as it seemed to be doing well… planet catfish mentioned aggression towards other cats…. though there are a handful of Cory’s in the tank, and I’ve not witnessed any aggression there either.
I don’t notice the normal pleco big poops, so hopefully he’s getting enough to eat… so far it doesn’t seem interested in anything I offer it, and spends the bulk of its time on the driftwood, it does spend some time on the glass, almost always the back, and is very shy, it goes under the big piece of driftwood if there is movement within 5 feet of the tank…
After several months, I’m noticing it out and about more often, as long as there is no movement in the room

Are you sure it is not the LDA060 based on "L177 is a variety with larger spots more obvious in younger specimens and LDA060 is a variety with ill-formed spots or flakes." The spots in your pic sure look like "flakes." But I also know how much many plecos can morph as hey grow. So the spots may also be considered largish as well. So I think at this stage you might be able to argue for either variant.

I am mostly a keeper of the B&W plecos from the same part of Xingu as your fish- the Big Bend.

Pretty much all male plecos are territorial. Sometimes adequate space and decor/plants to break up sight lines blunts the aggression. But plecos, like people, can vary in their attitude from individual to individual. Some are much more violent in how they protect their territory. One good clue that there is fighting ongoing is you will see the scrape marks along the flanks of the fish. When this is especially nasty you may see more than the white scratch marks, you will also see a red tinge to it.

In the wild there is usually sufficient space to a beaten up fish to be able to flee far enough to end the fighting, In a tank this may not be the case.

as magnified as the picture is, I think it's grainy, the spots are uniform pretty large for the fish size lemon yellow spots... that picture was taken like 5 feet from the aquarium

Got a few better pictures of my 177… one of the Pristellas photobombs the 1st picture & the darker of the zebra lace angels photobombs in the 2nd pic