Gold Nugget Pleco (L018)

The gold nugget pleco is one of the most sought-after L-number plecos, with bright yellow spots on a black background and yellow edges on its fins. It was sold for a long time under the numbers L018, L085 and L177, and was scientifically described in 2011 as Baryancistrus xanthellus. The similar-looking L081, with smaller spots, is regarded as a separate form.

Juveniles are sold as small 5–6 cm fish; however, it reaches 20–25 cm and becomes territorial. For this reason it is not suitable for small community aquariums.

It lives in shallow, fast-flowing, rocky stretches of the main channel in the Volta Grande section of the Xingu; the L177 form comes from the Iriri River. It feeds on algae and biofilm on sunlit rocks; the water is warm and extremely oxygen-rich.

• Volume: A footprint of 120 × 45 cm (about 300 liters) for one adult.
• Flow and oxygen: A powerful circulation pump and aeration are essential.
• Decor: Flat stones, rock piles and spacious caves; letting light reach the rocks encourages biofilm growth on them.
• Water: 27–29°C, with a 30–40% water change every week.

Mainly herbivorous; in the wild it grazes algae on rocks and the tiny organisms living in it. In the aquarium, spirulina- and algae-based sinking wafers and granules should be the staple; blanched zucchini and spinach can be added. Protein-rich food such as mysis or bloodworms can be given 1–2 times a week. It does not eat wood.

It is generally calm toward other species, but markedly territorial toward its own kind and other plecos sharing a similar habitat. During feeding it may push small bottom dwellers away.

Good companions: Calm, medium-sized fish that like warm water with flow: large tetras, Geophagus species, discus (in a very large aquarium).

Avoid: A second Baryancistrus (in a small aquarium), plecos of similar size, slow and small bottom dwellers.

In a normal aquarium a single individual should be kept. More than one individual can only be attempted in a very large footprint, with plenty of caves and visual barriers.

In the wild it breeds in rock hollows. Breeding in the aquarium has been achieved only very rarely; most individuals on sale are wild-caught.

It is sensitive to low oxygen and dirty water. Bacterial infections and starvation may occur after shipping; watch the belly line of a new individual. Fading of the yellow colors is usually a sign of stress or unsuitable water parameters.

Difficult to tell apart externally. Mature males have a wider head and more prominent odontodes on the pectoral fin spines. Females look slightly plumper in the belly when viewed from above; a reliable distinction can only be made in large, mature individuals.